 Pass things along to your host, Susan Barter. Go ahead, Susan. Hi, everyone. I want to let you know that also below the general chat, there are two handouts, so please feel free to download those. And also, if you have any questions, put them in the chat box and I'll make sure that we collect them to answer at the end of the Mary's talk. So the best way to keep in touch about what's going on with connecting to collections care is to join our announce list. You can also log us on Facebook or follow us on Twitter. And if you need help due to a disaster, you can ask for it at the 24-hour hotline. For the National Heritage Responders. We used to have a forum. Now we have Connecting to Collections Care Community. And you can join it and ask questions. I have monitors who are dying to answer questions for you. And they're not getting enough business. So please, if you have a question about caring for your collections, please post them there. And finally, you can contact me at this email address. I'm happy to talk to you. And next month, our last webinar of the year is on packing and creating. And that should be really interesting. Coming up in the new year, we have webinars in January and silica jails and microclimates in March on emergency planning for gardens and living plant collections in April on old loans in May on caring for a barrier. We have two courses coming up. One will begin in March on collections management with John Simmons. And the other is on rework and storage management. And that will be with Simon Lambert from CCI. So we look forward to those. And I'm now going to turn you over to Mary Coughlin. And we're going to talk about plastic. Thank you, Susan. And thank you all for joining in. It's nice I see some familiar names. And for the rest of you, kind of virtual hello. So my name is Mary Coughlin. I'm an assistant professor at the George Washington University's museum studies program. I'm also the head of our online program in museum questions management and care. This is a brief intro of how I got into the world of plastic when I was finishing up my graduate studies at the Winniter Conservation Program. The Samuel H. Kress Foundation gave me very generous fellowships to work at American History, Smithsonian National Museum of American History, back in 2005-2006, where I got to study nothing but plastic for a year. And I found it fascinating. And since then I've been lecturing on it and studying plastics as a material grouping. There's a lot to cover today, and it's going to get in and get going. So there are types of plastics. There's natural plastics. Those are things like corn, corn, hoof, tortoiseshell. There's also this middle group of semi-synthetics. And those are plastics that have a natural component and a man-made component. And those are things like cellulose nitrate, cellulose acetate. They're easy to know because their name, cellulose, is a natural component right there. And there's fully synthetic plastics. And those tend to have poly in their names, so polyvinyl chloride, polyethylene, things like that. Plastics come in many forms. Once you start thinking about it, you realize how diverse this group can be. You can have solid plastics, like foam blocks and sheets, even textiles. You can have liquids as plastics, so emulsions and adhesives, and composite forms as well. And again, you start thinking about your collections, your daily life. You realize plastics are everywhere. And then we like to group plastics. So there are three main groupings or types of plastics. And thermal plastics are the most common type. That's about 80% of our plastics are going to be thermal plastics. These are things that if they're seated, they can soften and you can reshape them. And then when they cool down, they harden into whatever form they've taken. In museum collections, this means that some of the thermal plastics can be vulnerable to creeping or deforming under stress, or even over time because of gravity, so how you're supporting and displaying plastics matter. Thermal sets, these are going to be ones that are hard, and you can't change that. They're permanently cross-linked and rigid. And years ago, I took a course at K-Event, and she's the one who introduced this idea of food. So for thermal plastics, the idea of chocolate, you could have it hard, but then you can remelt it and reform it, so those are thermal plastics. And thermal sets are like your chocolate chip cookie. You can't change that. You're not going to remelt the chocolate chip cookie. It is what it is. And then elastomers are sort of like the gummy bears. You push on them. You're going to deform them, but then they should bounce back to shape. Over time, they're going to lose that property typically, but that's sort of the main idea of elastomer. And this chart, don't get worried about it. It's just a brief listing of some of the thermal plastics and thermal sets that you might see in your collections. And then to also introduce you to the idea of the shorthand for how to write somebody. So those are the letters and parentheses after the full chemical name. So polymers. Plastics are polymers. So what is a polymer? Those are long chain molecules or monomers that repeat. And so polymers just repeating monomers. They go over and over again. Again, fully synthetics, we're going to call poly-something. So fully synthetics are polymers, and we're going to name them poly-something. So that's their tell-tale sign. So it's something, again, like polyvinylchlorate or polyethylene. It's going to be a fully synthetic polymer. Polymer scientists are the ones who make these fully synthetic new plastics. They can either modify natural ones or create new polymers. And this list, again, is just some of your more common poly, you know, fully synthetics that, again, you might see in your collections. And then their general date of introduction and the youth ranges can vary. So for plastic development, most polymers are actually invented on either side of World War II. And there's actually been no significant new plastics introduced in decades. It's kind of amazing when you think about it. So the polymer chemists typically are just modifying these existing groups of about 50 class classes of plastics. And the last sort of bar in your screen is it's fascinating and scary statistic that between 1950 and 2017, 8.3 billion metric tons of plastic have been produced. And about half of that has been since 2004. And most of that is from packaging. So it's a holidays approach and we do our convenience shopping online. Just know that that has a plastic price. Okay, so let's pull back to talking about the plastics itself and formulating them. So what sort of makes up a plastic, right? So you've got the polymer and you're going to have specific properties of weight, molecular shape, how much it's polymerized. Those are sort of things that, you know, that, again, the polymer chemists can alter to get the product that they want. And then you have additives put into that. Again, some of that is what you want the product to look like. So colorants and things like that and able to make it last longer. So you're going to put in UV blockers, maybe some antioxidants. Do you want it to be flexible? If you're going to have plasticizers, fire retardants, and that entire recipe then influences the way the plastic looks, what you can do with it. And then for our concerns in museums, how it ages and perhaps how it even deteriorates. So pull back and look at a bit of those plastic additives that seem to matter is how things can age for museums or why they're in there. So then plasticizers are added for flexibility. Think of spaghetti. Again, this is something I learned long ago again, this idea of you're going to add oil. And if you don't add oil to a spaghetti, it's going to get hard and rigid and sit there. But with the oil, it's going to be flexible. They're going to slide over each other. So the role of adding a plasticizer is to make the plastics more flexible. Where the takeaway for museums is, okay, so this plasticizer is in there, but how is it bound? Sometimes they can actually start to work their way out. If you've ever seen a plastic that's been weeping or oozing or deforming, that could mean that it's actually losing its plasticizer. Another thing that tends to be added is antioxidants and UV blockers. And here it's actually an image of a cell machine that all of my kids have used when they were babies. And the side that states the window turned really yellow. It's supposed to be white and it turned really yellow from sun exposure, honestly, in probably about nine or 10 months, it turned yellow. And you can see the side that states the room is not yellow. So to me, that said, oh, whatever antioxidants and UV blockers that were put into this plastic item have been exhausted from exposure. So again, why is it in there? What's the takeaway for a museum that it's got antioxidants and UV blockers in the formula? It's there because light's going to matter and oxygen can also accelerate aging. And then heat stabilizers are also commonly added. And for museums, that's going to say, oh, temperature matters. Lower temperatures, slow chemical reactions. And higher temperatures can accelerate chemical reactions then, right? So where we're storing our plastic and the temperature that is reached affects how our plastics are going to age. And actually, let me take a moment. Susan, can you, I realize I forgot two polls, but I just want to see now, I think it would be a good time. So I'm curious, do you know the types of plastics in your collection? And then once you answer that, I'm curious, how do you know the type of plastics in your collection? Seems like most of you know some. You're using things like your accession files, the look of them, time period manufacture, that can be really helpful. And then not surprising, most people don't seem to have access to scientific analysis and spot tests. That's pretty much limited to conservators or conservation scientists available to you. So the appearance seems to be guiding a lot of this as in time manufacture. Okay. And then, Susan, let's also just, let's ask about are there deteriorated plastics in your collection. From what you're seeing, do you guys see, oh yes, okay, probably why a lot of you decided to come on the webinar today is because you know you're having some deterioration in your plastics. It's okay that some aren't sure, but you can really need one of my seeing. Great, that's good to know. Thank you, guys. Well, along the lines of deterioration, agents of deterioration, right, that framework that came from CCI affects plastics as well. And so all the things you see on the screen here, those 10 agents can affect plastics. Okay, and some have, certain types have more influence than others. We'll get into some key things with plastics in a second. One thing that's also just realized when we recycle plastics, the products that are made from that recycling turn into something called down-cycle plastics. These are actually lower grade plastics than virgin plastics itself. And anti-aging additives typically are not replaced, so they're not getting things like UV absorbers or blockers or heat stabilizers. That just takes too much money. So in essence, the product that is then made in the down-cycle product is actually weaker than the original product would have been. So as these things are developed and coming to our collection, that could have a real impact in the aging that we're seeing when we're trying to care for this stuff. Also, bioplastics are becoming more and more appealing and common. And that's because we want them to come from renewable sources so that we're not relying on this plastic formulation from primarily petroleum. So you've got biodegradable plastics. We've seen grade because hopefully they will biodegrade in the landfill. But for us in museums, that's harder because if they're meant to degrade, how are we preserving them? There's also bio-based plastic, and these are going to come from basically synthesized plant sources. And for those who are involved in 3D printing or have 3D printing materials in their collections, know that a lot of that 3D printing plastic is something called polylactic acid, and that's going to come from corn and sugarcane and other biological sources. And those will break down at high temperature and relative humidity environments. So, again, knowing what we have in our collection and what we can expect for them for aging risks is really important as is the environment we're storing and displaying the plastics at. Most of what we use in our daily lives are commodity or consumer plastics, and these are sort of the six most common that you see on your screen. And I just wanted to point out that polyethylene is the most common plastic today in both its form. In the case you're not sure, like, well, what do these materials actually make, Mary? Well, let's go to the next slide, and you'll see where those common commodity plastics come out in our daily lives. And again, quick look at this. I'm sure you've interacted with some of this today, either at home or at work. And then also start thinking about your collection, what kind of stuff that's listed is in your collection, and let's talk a bit about risks that some of these do face. And again, getting back to that question of how do I even know this type, right? So some of you said that you do look at trademarks, maybe know some trade names. The website you see on your screen, it's under Bakelite, but there's a lot of trade name information that maybe is in your accession files, maybe marked on the object itself to help you understand what this could be. And again, when I was doing that Crest Fellowship years ago, I was faced with this idea of I don't know what all this plastic is, what can help me. And I decided that making a timeline was helpful because sometimes if I could go to the accession files, I'd a date either for manufacture, when I entered the collection, maybe combined with appearance and use and form, I could then narrow down what the potential plastic was, and then I could have a better understanding of the potential risk that it faces as it ages. The highlighted ones you see in blue are going to be the ones that we're going to see today. And they're going to have been coined years ago as Malignant Bastic. These are the ones that interaction we just know can have a negative impact on plastic amounts. First, we're going to talk about this early one, and that's Harbour. It's down to E30s, 1840s, turning into a hard rubber, things like Volcanite and Evanite. And it's made from adding sulfur to rubber. And it's really that sulfur that's going to affect its aging. So it can actually off-gap a pure cactus, which I think we inherently know is not great. It's often ground greenish out of its ages. And as it deteriorates, it's really vulnerable oxidation. So that can be a reaction to oxygen in the environment. So if we present if its weight can be sulfur, again, there's a real force for sulfuric acid that can form in the negative materials nearby. And then just kind of curious the brief interview, overview, curious how many people think they have hard rubber in their collection. So it's going to be a quick poll about that. And it tends to be really dark. The ones I've worked on are things like match cases around Civil War era in the U.S. about 1860s. So yeah, so we have about half of you think that you've got some hard rubber in your collection or so. So I'm not sure. Okay. And I'll be pulling you on those malignant plastics just to see what people think they have. Okay, perfect. Thank you. For hard rubber conservation, there is actually thought that it's going to benefit from oxygen-free storage because oxidation is the main mechanism for its deterioration. So oxygen-free storage or anoxic storage is when you are storing something, you're storing the oxygen out. It can be hard to achieve, but you sort of know that. Also, in general, you want about 35 to 45 percent RH. We're going to move on to cellulose nitrate, which is going to be a bigger topic to cover. It gets introduced about 1860s, and it's used as both an explosive and as a plastic. So again, not too surprising we see some issues with cellulose nitrate. It inherently is translucent, but colorants and cellulose can be added so you can get a variety of looks. So if you deal with, like, cartoon cells, that's going to be cellulose nitrate, typically early on. Also, trainings like parkesine or celluloid, that's going to be cellulose nitrate, ivory, xylinite, those are names given to imitation cellulose nitrate, ivory. Also, French ivory is a term that you might come across. And on the screen you see a variety of, in this case, those are shoe horns, but they give an idea of the variety of look that you can get with cellulose nitrate. It was really, really diverse. It's made by soaking cellulose pulp in a mixture of nitric acid and sulfuric acid. So again, we're not going to be too surprised if we can see issues with the nitric acid and sulfuric acid that is mixed in. The curating cellulose nitrate emits nitrous oxide that can be converted to nitric acid by moisture. So again, to pull back our big takeaway from museums is, oh, wait a minute, the relative humidity I'm keeping my cellulose nitrate collections in matters. And that hydrolysis or that reactive breakdown starts at about 50% RH. So if you stop and think about your collections, 50% RH can be really hard to achieve and maintain for a lot of spots. But if you have cellulose nitrate, you do want to try your best to keep it below 50% RH. As that nitric acid comes out or other plasticizers come out, what can start to happen is you can get small holes for me from the plasticizer working its way out. And then your surface moisture can sit on that, work its way inside those holes, and you can actually have nitric acid forming on the interior of your cellulose nitrate. So sometimes you might not even have a surface reaction. You're actually having it form inside of the object itself. And here you see some startling images of cellulose nitrate deterioration in three-dimensional solid forms. And for some of them, you can see how much darker or browner they are actually in the inside. And again, you can almost then picture as that plasticizer worked its way out or the moisture worked its way in that you have the nitric acid forming on the inside. In this image, you see a storage drawer. And this is just me going around doing, you know, a conditioned check, survey of, you know, let me see what plastics are in collections. And I opened this one and thought, oh, something's happening. And do you see that little box? I'll just describe it. It looks like it's falling in on itself. It's like a tortoise shell appearance. Well, that is really, really falling apart cellulose nitrate. And as that degraded, it was releasing that nitric acid off-gassing. And then that was spreading. I'm sorry, I'm having trouble figuring out the, there we go. Thank you. So as this deteriorated, this one here, the off-gassing was then spreading. And you can almost picture it hitting the various metals. So this is a copper pot back here. And this is all copper corrosion that forms. And then as it's spread and moved, it also caused copper corrosion here. All that acid would have been absorbed by any of the organic material in there. So all these boxes would be absorbing the acid, certainly the wood itself. Not great to store the plastics in wood, but that's okay. So again, sort of looking around on your collection storage or your exhibits, if something is happening, particularly if you have metal deterioration, you can't explain, and there's plastics in that area. You might start thinking, oh, I wonder if the plastics themselves are a source of this corrosion. Here you see some deteriorated solosnite trade films in rusted containers. And some of you may be dealing with film collections, so this may be something that you are used to or have seen. Here's the first toothbrush with nylon bristles. It just unfortunately had a solosnite trade handle. And so you can see the entire handle just crumbling. Somebody knew that it wasn't ideal, and so they actually put it on a metal spatula, which maybe you can make out here. And then fortunately wrapped it in saran wrap and then put it in its own plastic box. And so it sort of just sat there off-gassing and sitting in its own assets and really started to severely degrade and fall apart over time. Take a moment, and so far who thinks they have solosnite trade in their collections? Let's do that poll. So actually a different poll for it to be poll number five for solosnite trade collections. There we go. Thank you. It looks like a lot of you are thinking that you've got some solosnite trade. So that again, that could be three-dimensional, that could be solid, that could be film, cartoon cells, right? That is a common use plastic, and unfortunately one that we know is malignant. The good news as you think about your collections is that if you have imitation ivory solosnite trade, that does seem to age typically a little bit better. And the thought is that the zinc oxide that is used as both a pigment and a filler in these three-dimensional objects can actually act as a stabilizer. So the zinc converts that bad nitric acid to a stable zinc nitrate. And also the thought is that the zinc oxide is actually also working similar to our own, if you use sunblock with zinc, that it's actually going to physically block out some of that UV damage from the light itself as well. This came up in a collection I was working at because the curator wanted to do a large solosnite trade accession. And so I said, okay, let's just go see what you have and I'll monitor them, and we won't accession anything that seems to be doing poorly. And so we use something called Cresol Purple or Cresol Red Monitor. And you see that here. They are sensitive to only deteriorating solosnite trade, so they have to be off-gassing. And they will turn from this yellow color to a bright, bright pink in the presence of nitric acid. Again, only for solosnite trade. And here you see monitoring of one object after a day and after a week. And so you can see, again, that bright pink means that, yes, off-gassing is happening and that off-gassing is spreading, so you don't want to accession that one. When you turn that object over, you can see how deteriorated it was on the back side. And I think if the curator had looked on the back, she wouldn't have even considered accessioning it. But again, that is all that cracking, that crazy, that crumbling. It's all typical of sun solosnite trade deterioration. And here again, you see those creosal purple strips. There's another object and you see that the acids are spreading over time and it's reacting that monitor. So solosnite trade conservation, you want to monitor for off-gassing if you can. Relative humidity matters. If you can do cool or cold storage, that is great. You're going to slow down your chemical reactions. If you can't do that, you want to ventilate. You don't want that nitric acid to be able to build up. So you want to do some ventilation. And storage, basically your standard blue board seems to do pretty well for this material. We're going to move on to silo acetate. It's introduced about 1910. Some of the trade names for it are things like Safety Film or Lumerous or Tenite. It comes in different grades. It's used in very similar ways to silo nitrate, but it was introduced because they realized that silo nitrate had some issues, you know, films catching on fire, simultaneous combustion, things like that. So it's used slowed in about the 1960s, but you can still find it today. And actually, their softened silo acetate may come back in popularity because when it degrades, it just breaks down into silo synacetate, and essentially vinegar. So it's actually a biodegradable plastic. So as we get more environmentally aware, we might see more silo acetate. It's made from silo pulp, acetic acid, and sulfuric acid. And as it degrades, it can give off the tell-tale vinegar smell, which is the acetic acid, right? It's vulnerable at 50% R8. So that, again, is vulnerable to hydrolysis, so R8 matters when you have silo acetate in your collection. You can tell that it's losing its plasticizer, so even beyond that vinegar smell or vinegar syndrome can be things like it starts to get tacky, weeping, it might warp, it starts to break, and the image on your screen is actually silo acetate glasses that have degraded and clearly broken and changed. This is a fascinating object in that it is a salesman's kit with about 50 silo acetate color samples all strung onto metal cordage. And the thought is, okay, it's the same manufacturer. They've been strung together, so we can assume they've been exposed to the same environment, but these materials did not age the same at all. Some are perfectly fine, some others were really severely degraded like that you see on the bottom of your screen. You can also hopefully tell that some of that has deteriorated or corroded the metal chain that they're on and changed colors. Some are actively weeping, some have lost all the weeping material and are now cracked and breaking apart. And if you want to know a bit more about this, it's in a studies and conservation article from several years ago, you can check that out. These are deteriorated cannelling or buckling on silo acetate film. So again, if you've got silo, nice treat, or silo acetate film in your collection, you really, really want to get in there and scan them and get that collection digitized before you lose the content. I always like to show this, these are organic samples. So this is potato slices and silo acetate from the 1940s. And mosquitoes and polymethylmethacrylate, which we commonly call Plexiglass from the 1940s. The same person was studying these, just used different plastics to embed them in and you can see how wildly different they aged over time. And just to stress, how many people think they have silo acetate in their collection? So let's do that full. Again, a lot of you are thinking you've got some silo acetate. It looks like. So I'm not sure, that's understandable. All right, let me get it. It comes in many forms. So film and three-dimensional as well. For silo acetate deterioration, it's that acetic acid that's coming out that can really cause damage not only to the plastic itself, but to the things around it. So the degradation rate is double if acetic acid is not removed and the TH reaches 4.6. So knowing if the acid is coming out is really important. In the past, the idea was to scavenge those acids. So we recommended absorbents like zeolites used to try to counteract that buildup. But actually some studies, particularly by Yvonne Shashoa, show that actually maybe using zeolites with plastics was actively pulling out plasticizers. So that's something we sort of pulled back from a blanket recommendation. They can help in certain circumstances, but unless we're sure you shouldn't use things like zeolites and absorbents, that's going to be things like activated charcoal with plastics. Again, storing a blue board, your standard archival corrugated boxes actually seems to do pretty well. And here you see an example of that. So those are some natural specimens encased in cellulose acetate and then stored in stacked up blue board boxes in a way to try to not increase the footprint of storage, but to also increase some ventilation to try to get that off gas and removed and vented out. In cellulose acetate like cellulose nitrate, you want to pay attention to your relative humidity and keep it below 50%. Cool or cold storage is ideal. It's going to be easier said than done, I realize. And ventilation should be a standard default. Monitor for off gas. And we're going to get into how to do that in a bit. And storage in blue board is also just a safe default to think about. Sometimes you have cellulose nitrate and cellulose acetate together, and they are not friends at all. Here is a coat with imitation ivory cellulose nitrate pin, which they themselves, we think, would age OK. But you have a cellulose acetate fabric lining of the coat. And where the backing of the pins and the cellulose acetate fabric interacted, you get fume fading. And so you see that white, that sort of yellowish white color on the pink lining. And so that's the reaction between the two together. And it's an inherent vice if you keep the pins with the coat. Here you see cellulose nitrate and cellulose acetate mathematical models. So you have a cellulose nitrate interior form in case by cellulose acetate sheets form on the outside. And again, if you look at that one on the left, you see that it looks wet. That is actually a plasticizer weeping out. And it's buckled because as that plasticizer is coming out, it loses the material, it's losing mass, and now it's deforming. And it's actually causing the whole cube to pop open. The detail image on the right is like a pyramid shape. And as that side has lost plasticizer, it at one point would have probably looked wet and weeping, but it has lost all of its plasticizer, so it actually started to dry out and curl up on itself. So that is actually rock hard and rigid. You touched it and it would basically want it to shatter. And again, those two do not do well together. They were the accessions by the museum. And here you see one sheet that in the previous slide would have been wet and weeping. And then once it was removed to a drier relative humidity, it actually, the weeping material started to crystallize. So again, relative humidity and environment really matter when it comes to plastic collections. We're going to jump to polyvinyl chloride, a more commonly called PVC. It was invented in 1927. We typically just call it vinyl. It's made from ethylene from natural gas, reactive with chlorine to get a vinyl chloride monomer. That then just keeps repeating, which is why we call it polyvinyl chloride. It's one of the top selling plastics in the world. It's cheap. And for a while I thought that it was chemically stable and safe, but we know better now. If you have vinyl record collections don't freak out. Those actually tend to be pretty stable because they are rigid. It's really the plasticizer additive that causes an issue when it comes to PVC. About 30 to 40% of the weight of plasticized PVC can be from plasticizers. And it's not a strong bond. They can start to work themselves out. And some of the plasticizers are toxic. So things like salates, which makes the PVC soft and pliable. And they can be found in all sorts of clothing and shower curtains and for a while children's toys and things like that. And they're not healthy for us. We want to be aware of that in our collection and in our lives. For PVC deterioration, temperature and light induce a degradation. So again, we want to pay attention to our storage and our exhibit environments for PVC. And as the plasticizer migrates out, it can start to change the look of the surface. So it can be tacky. It can look like a bloom. It can change a bit of the color. Here you see one of the original Barbies. And you can see that she is not an even color. And part of that is the varying degrees of PVC degradation that's occurring. And actually, I found out the other day that the hair on some of these dolls can also be PVC. And here you see this image, this heartbreaking images of PVC deterioration. And these are all museum collection objects or would have been. For the mask, this was from a 1950s TV show with on display for a long time. And then when it went to go get de-installed, somebody went to go remove it off of the mount and it just shattered. Because over time on display, it had just lost all of its plasticizers. So it wasn't poor handling. It wasn't a poor mount or anything like that. It was just the end of the plastic lifetime. The watch that you see that looks yellow. It originally would have been clear. The brown folds it up off the material that you see on the lower left corner that at one point also would have been clear. This was like a plastic covering for a typewriter or a dictaphone machine. And over time, again, if you pushed on that, it's actually wet. Or if you go to unfold it, you could actually hear it peeling apart. And then on the bottom right are a detail of electrical cords made out of PVC. That are stored in a hot environment. And after it forms, it sort of looks like they're melted over time. So let's take a moment now and do the poll of how many people think that you've got some PVC in your collection. It comes in various forms. And this could be unclassified PVC, plasticized PVC. Also, for those of you who may be thinking about your home, don't worry about PVC pipes. Those are rigid. Again, really it's the plasticized PVC that we see the most. Degradation and issues with. So it looks like most of you have PVC in your collection. And if you are not sure, that's understandable. Great, thank you. Safety goggles. Besides the safety goggles tend to be PVC so that they're flexible and can mold to your face and keep away any, you know, splashes that might happen. And as an intern once I was asked to go look at the safety equipment for emergency. And then I looked at the safety goggles for emergency. And then I looked at this and thought, oh, I don't care the emergency. I don't think anyone should be wearing these. And what happened was the PVC flexible side were just weaving their plasticizer and actually so much so that it was cooling and being absorbed by the box itself. And honestly, the industry knows that PVC does not have an indefinite life span. We like to think that things will last in our collection. But again, industry knows that they won't. So this is just a quick table. Take it from the book, The Concentration of Plastics to show you the average lifetime and years that we expect from these basic PVC products. If possible, for all of these plastics, it's great if you can identify them and store them together. Let's all shuffle because we know that that's easier said than done. It's not maybe even realistic for the way our museums work or how we want to be accessible to researchers. But if you can at least identify, maybe you can then go back and flag and assess and survey them over time. For PVC, you want to be careful about heat and light. And again, keeping them in about a 35 to 45 percent RH seems to be pretty stable. PVC differs a bit in that a lot of plastics, the safest default is okay to ventilate. But with PVC, studies have found that actually storing in a nonabsorbing container, something like maybe glass is actually good so it's going to slow that migration of plasticizers out because it's sort of reaching equilibrium with the environment around it. Also, putting in a freezer or cooler cold storage is pretty good at stabilizing or slowing down the degradation of PVC. Never, ever use absorbents like zeolites with PVC because it will actually actively pull out that plasticizer so you're actually hastening the deterioration. We're going to step now to polyurethane. It's invented in 1937 by Bayer in Germany, which because of then World War II, you don't really see its use internationally until after World War II. Commercially mostly available in the 1950s. Polyurethane is a big class of plastics in that it can take so many forms. It can be elastomers, it can be foam, coatings, adhesives, fibers. So we're going to dive a bit into the different forms of polyurethane. For those dealing with textile collections, some of those may be polyurethane. And that's going to get you your stretchy fabric. Some of us are probably even wearing them right now. Things like spandex and lycra, bathing suits or two-way tricot, those are all going to be polyurethane fibers. Thermal plastic polyurethane are going to be things like coating, adhesive, paint, sealant, you know, put polyurethane coating on your deck, that kind of thing. Again, still the same class of plastic as polyurethane. What we probably mostly see for polyurethane or think of when we hear polyurethane, it's going to be foam. And about 75% of polyurethane is made into foam. And those are going to be things like cushions and mattresses. We sit in your car seat underneath that. It tends to be polyurethane foam. And they can also be rigid in the form of insulation. So now that polyurethane foams are equal, there's two types of those. There's polyurethane ether and polyurethane ester. And the ether form is most vulnerable to photo-oxidation. So it's going to be oxygen or ozone and light. It starts to powder at the surface, yellow and discolor. There is actually a conservation treatment, which gets called a sunblock treatment option for those. The ester form is really vulnerable to high relative humidity. So again, keeping an eye, monitoring our environment with plastic is really, really important. Once a lot of these deterioration mechanisms take hold, they're autocatalytic, which means they're going to progress really, really quickly. So just keep that in mind. We want to avoid that part. So polyurethane foams, okay, well, do I need to know if it's an ester ether? Probably not. But if you have the option for doing a treatment for conservation, then, yeah, the conservator or conservation scientist should identify what type of foam it is. But for those in most collections, let's just make some broad assumptions when it comes to polyurethane foams. We know that they have large pores, which means they have a lot more surface area than some of their plastics, which means there's a lot more sites for reaction, which in some ways makes them really vulnerable. They're going to be light sensitive, but just taking them out and keeping them in the dark doesn't mean that they're going to last forever. They can degrade in the dark as well. And over time, volatile organic compounds or VOCs can come out, particularly at high temperatures. So again, keeping them in lower temperatures is important. And oxidation, if you can get them in an oxygen-free environment, they will last longer and easier said than done. With all of that in mind, it's hopefully not so surprising when I then say that people are finding that coated or painted foam seem to be aging better because they're blocking out a bit of that environment reaction. A non-coated foam lifespan or your useful lifetime is about 20 to 25 years. So then let's think about some polyurethane foams that may be in your collection, or exposed. Start thinking, okay, what is their usable lifespan? Do I want to get them out? Do I want to get them displayed and studied now before they severely deteriorate? Or at the very least, I need to document them now. Know if they're deteriorating? Do they look yellow? Do they look discolored? If they're supposed to be a cushion, if I put some pressure on them, do they bounce back? Or does it just sort of stay? I think we've all sat in older chairs and you get up and you can still see the outline if you're behind. So, oh my, but a lot of that, again, is that's because the polyurethane foam is now deteriorated. It's not bouncing back. It's lost that elastomer property. Here you see the interior of basically a trucker hat that all of that polyurethane that would have been in the interior has now cropped off onto the surface of the interior foam. And then some good intention people had embedded or, in cavity case, a metal object in polyurethane. So that's not great. You don't want to store it, but you don't want to use polyurethane for storage. Before we get into this, just take a moment and how many people think that you've got some polyurethane in your collection? And again, this is a big, this could be fibers, this could be foam, this could be, could be coatings or paints, adhesives. Yeah, it looks like a lot of you think you have polyurethane and I bet you're right, in a lot of diverse forms. Perfect. And just as a quick aside, there is a treatment for polyurethane ether foams. You just have to know what it is. And anoxic storage or oxygen-free storage can be really helpful, but again, not that easy. If you can't do anoxics, then ventilate because again, you don't want those VOCs building up. Try to realize that over time even polyurethane foams can get tacky. So you want to keep in mind point of contact because you don't want this stuff to start sticking to each other. So can you interleave it with something so that it won't stick? Low RH storage is best. Taking it, you know, limiting UV, keeping it in the dark as possible is all important. So plastic textiles, fibers may be polyurethane. They can also have a PVC or polyurethane coating. We see a rapid development of man-made fibers in the early to mid-20th century. And this can be on things like banners, textiles that we're wearing. And finer fibers have a high surface-to-volume ratio, making them more chemically reactive to light and photo oxidation and thicker ones. So again, with a lot of polyurethane, it has to do with the fact that they just have a lot of surface area to react. Okay? Unlike three-dimensional plastics, objects, still more coatings that have the same composition of age plastic fibers appear to be more physically stable. And part of that is that the fiber orientation that they're getting made, the outer skin is more crystalline, so it's more ordered. It's actually going to block the environment a little bit better. And then the core is amorphous, so that's what's going to give it its flexibility. So in some ways, plastic textiles, even though I say, oh, they're polyurethane, they might age better than polyurethane foam. Okay? So, okay, we're going to pull back for a second because that was a lot of information thrown at you. And you still might be thinking, well, I'm not sure where I'm seeing some issues. And I was in the same position years ago, and so I made this chart that's on your screen now. And I thought, well, maybe if I can say what the form that I'm seeing the degradation in, can I then use that to identify potential plastics? If I'm seeing something that's tacky and weeping, then I would pull back and say, okay, well, what plastics tend to be tacky or weeping? And then I would use other information like the date it was used or the accession file to then try to narrow down possible options to understand what the material could be. I found this table helpful when I was looking at plastics that I wasn't sure what they were. And then once I started thinking, yay, I understand these malignant plastics and I can see what they do and I'm understanding the chemistry and then as I was poking around the collections more and more, I would see things that I couldn't explain, such as you see on the screen, these electrical implements, and these are made of vacillate. And we tend to think of vacillate as being a strong or a plastic that ages well, but I would see these weird bloom or haze forming. I thought, oh, what is going on? Well, we do think of vacillate, which is wood, flour, paper, spectra, and other fillers added to senile formaldehyde resin. The trade name is vacillite. It's a good heat insulator, so I'm going to see it in telephones and electrical plugs, radios. We do think of them as single, but they can form a bloom over time and you should block out UV light with them. I want to highlight this case study real quick. This is a big wheel bicycle that was in storage. It has vacillite handles and it was fine in storage. It was when it was put on display that relatively rapidly we noticed that a bloom was starting to form. So to me, this is a prime example of how environment matters with plastic. It was in a storage environment that it was fine and something was very different in the display environment that the handle started to bloom. And we looked at light levels and temperature and relative humidity, and we never really found a reason why it was changed. The thing that we couldn't answer, and we didn't have time to study, was whether or not there were other pollutants in this environment that reacted. So again, environment matters with plastics. It's a big takeaway for this slide. Some now think that polyethylene and polypropylene may be our plastics that we should be avoiding, especially if we're going to think of them as archival storage materials. And this is so much easier said than done and I realize that don't store plastics in polyethylene bags. If you have plastics that are in bags because maybe they were weeping or you had a smell and you wanted to protect other things, let's get them out of that polyethylene bag because the polyethylene itself can actually actively be pulling out things like plasticizers. So good intentions, but let's get the plastics out of polyethylene bags and realize that even polyethylene, again, for a long time we think of them as stable and some of them tendy, but think about some of the old Tupperware or plastics, you know, food storage that you might even have at home. Sometimes those go pretty tacky. They maybe start to yellow or change color. And here you see one of the original Tupperware in storage and that certainly has gotten tacky and started to deform over time. I was curious, there's another poll wondering how many people have noticed any polyethylene bags or sheeting in your collections that have started to yellow over time, sort of like this image that you've seen. Curious if you've seen that. Yeah, so about five years or so you have, you know, a little more than half. And this is something that, to be honest, I think conservation and conservation science needs to study a little bit more about what exactly is happening. So we understand these carbonyl groups are forming and that's what's causing the yellowing and maybe antioxidants or UV blockers are getting used up. But is it okay to keep storing these things, you know, objects in polyethylene bags? Is it okay once they're yellowed? Are they still stable? And in my opinion, what I've come across is I feel like we don't have a hard-and-fast concrete answer on that. So I would like to see actually more work done for that because, again, a lot of you were seeing that in your collections and then do I still use this? This is a big question. Let's take a moment now and pull back and think about, okay, great if I know the plastic but maybe I just need to know how to treat all my plastics or are there big overarching recommendations that I can make? And so this is what I'm going to try to do now, which is really look at the environment, the environment matter, so you need to monitor. You need to pay attention to temperature and relative humidity. Keep these things in dark or low light as much as possible. But I'm not saying don't display them. I'm not saying don't get people access to them because that's the whole point of collecting where we want to share that information. Think of plastics as permeable. They're going to take on things around it. So even if a stable plastic, even if you have a plastic that's stable, if it's being stored or displayed next to a plastic that is unstable or off-guessing, that stable plastic can take on those assets itself. Also avoid stress. Think of how it's made, maybe those points of fabrication or where you're going to see deterioration first. Also labeling, how are we labeling these things? If we're using things like solvent acrylic barriers and whatnot, that's actually, that's a chemical stress. We want to not label things with that. We want to avoid stress. And then if you see a change in the physical form of the object, that often means it's losing something, whether that's off-guessing or it's losing plasticizers. If you see something distorted or warped, pay attention to that. Something is changing with your plastic then. Then elation tends to be a good default. It's not best for PVC, but if you're not sure what it is, honestly, that, if you don't have the resources to figure out the exact type of plastic. Using acid-free or buffered storage trays like blueboards, that's a good default. And let's avoid scavengers. So let's not use things like zeolites or activated charcoal. And monitor. Keep an eye on this stuff. Right now I want to walk you through AD test trip for monitoring. This AD test trips were developed by the Image Permanence Institute. Personally, it's acetate films. But in conservation, people started using them to monitor up-guessing acids. So they reacted with a variety of off-guessing acids. And they started with blue. They go through stages of green to yellow, depending on the amount of acid present. So the more yellow the reaction and the quicker the reaction, the more acid it's present. They're not meant for a long-term monitoring, which means you shouldn't just leave them in storage and leave them in a very light-sensitive, which you can use them to monitor plastic for about a week or two. If you have a plastic you're worried about, what you want to do is put it in a sealed environment so that any off-guessing is going to build up and that you're going to want to put a monitor in that and then periodically check on it for a color change. And here are some examples of a color change. So in the first slide that has these rods that say celluloids, that really bright yellow is an AD test trip that reacted in honestly about a day. So it started off as dark blue, and it's so much acid present, it became that bright yellow, the most acidic reaction that those strips can have. But the other ones have positive ones too, right? So that's Mr. Peanut on the lower right who turns sort of turquoise. That is a positive reaction. It's just less acid is present. And you can see other green reactions and some acid spreading. So again, those are AD test trips. Those are really, really handy to understand if you've got acids present. Now you see metal coupons. So basically pulling off of the AD test, but for long-term monitoring, if you're not doing an AD test, you're just using the same type of coupons. So there's a copper, silver, and lead. And then you can leave these in place for long-term monitoring. And if you see your reaction, if you see deterioration, you see corrosion on the metal itself, then you start wondering, oh, is the source acid coming off of my plastic? And on the left, there's a copper coupon which was left for one month in a severely degrading and off-gassing phthalos nitrate collection. And I mean, look at that copper corrosion. And then the right is the copper reference sample so you can see the degree of changing. And then once this happened, I immediately thought of the Antoine Pezner work, which is unfortunately what phthalos nitrate, copper, and iron sheeting. So that is just a tell-tale find from Yale University about inherent vices, plastics, and metal. They do not get along well. We'll take a moment to talk about handling. A lot of these components and plastics that can work their way out, the plasticizers to salate, things like that, can be toxic. So for your own health, you want to wear nitrile gloves. And you want to then dispose of the nitrile gloves once you've handled the deterioration plastic. You don't want to reuse your glove and touch something else because you can spread those toxins and things around. No cotton gloves when it comes to plastics. Let's use nitrile for our own safety. Think about labeling. Again, not using lacquers. And if use of solvents, that can be a point of stress. We see on the top some bubbling that's happened and you can't even read that number anymore. So using things like soft pencils, tie-on tags, labeling the non-plastic items is the thing you want to do when it comes to labeling. And let's look at storage itself. So it's in how we're storing our plastics and if we're using plastics for storage. Again, I want you to stop and think about your own collection. And are you using things like plastic film sleeves or slide sleeves, which is what you see here? And some of those are going to be PVC. And here you see little American slide pins stored in PVC binders. And if you can see, it looks like that PVC binder sleeve is undulating. It looks like waves. And that is a sign that we've got material coming off. It's losing plasticizer. And it itself is deteriorating, even though the intention was, oh, this is archival storage. It's not. Again, looking at temperature and relative humidity, your environment is so important, right? So we kept saying for some of those, oh, we want to avoid 50% RH. And here is a monitor one year from a storage room. And you can see that in cases it went above 65%, not infrequently. You have 20% RH changes in a relatively short amount of time. In some cases the temperature went up to 78 degrees Fahrenheit. That's all too warm, too humid when it comes to plastic storage. So monitor and pay attention to the environment. Low temperature storage is great if you can do it. You're going to slow the chemical reaction. Even ordinary food freezers can be okay for that. You want to insulate or double bags to prevent condensation with your plastic. And just realize that a lot of them can become stiffer and brittle even shrink a bit in cold storage. So you just want to slowly acclimate as you bring them back out. Again, realizing that it is not going to be answered for everything, but in certain cases that can be very helpful. For documentation, do it when it comes to plastic. You can also rebar your plastic. You're never going to look at it because of its uptake. So take your documentation. And then it's also really helpful to have good images and great documentation to then use that as a reference later on to say, oh, has this changed? And so you will thank yourself in the future if you did documentation now. And the accessing. For somebody's plastic, they're just at the end of the life. For somebody that's got the off-gassing one, there's a negative effect material nearby. And so maybe the accessing is part of the thing you need in your toolbox when it comes to plastic. And I'm answering all things that have to be a question from somebody that's looked at. So I like lists. It's how I think linearly, I think. And so when I was working on this, I really thought, okay, I need step-by-step. So if I'm in a collection, I'm not going to panic. So I always like to share this when I talk about plastics with people. So I wanted you to go in. I wanted you to observe. Look at the plastic. Are there any changes to it? Yes. Sorry, interrupt. There was a little bit of an issue with audio a moment ago. Oh, I'm sorry. Would it be possible just to go back to the deaccessioning, please? Sure, thanks, Mike. Great. Thank you. Sorry about that, everyone. I'm sorry that I missed Mike's message. So just saying that deaccessioning should be something that's in your toolbox when it comes to plastic. I know it can be an uncomfortable topic, but certainly if your plastic looks like the ones on your screen or they're off-guessings who degree that you can't figure out how to safely store them anymore, maybe that's when you have a conversation about do we keep these things anymore? So deaccessioning can be something that is very viable for plastics. And that gets back to that idea of, hey, hopefully you've documented it. So even if you do a deaccession, that information can still live on in your collection. I think it's helpful to just understand you have a step-by-step approach so that when you're in collections, you don't get overwhelmed. So I always say, go in and observe, look around. Do you see anything that looks funny or different with your plastic? Is it weeping? Is it cracking? Is there a smell you can't figure out? Is it warped, discoloring? Is there a bloom? Okay, if so, if your plastic looks different or weird, it's probably deteriorating. Also look at the plastics nearby. Are there metal corrosion that you can't explain? Are other things, you know, organics nearby, do they seem yellowed in a weird way or something, you know, is happening? Well, maybe your plastic is the cause of it. And look at the metal components of your cabinets and shelves themselves. Are they deteriorating? Is there a smell in the cabinet when you open it? If so, your plastic may be the source of that issue. So go in and observe. And then you're going to want to confirm your observations. If you have cellulose nitrate, that's maybe you're going to do the crystal purple or red strips. You're going to pursue this nitrate only. Or maybe just get some AD test strips and see if you can monitor for off-gassing acids that way and flag issues for a long-term monitoring. Again, maybe using those metal coupons, the silver, copper, and lead, and periodically looking for corrosion with those. And then if you think you have an issue with plastic, figure out if you can separate them so that they're going to stop affecting materials nearby. And then clean that form of storage area. Don't reuse a storage box if you think a deteriorating plastic was in it because whatever you're going to put in next can react to whatever acids that box has taken up. And again, look at the environment. Monitor for temperature. Can you lower the temperature? Look at the relative humidity. Can you maintain it? Are you getting too high? If you have cellulose nitrate and cellulose acidity and you know that they're in a collection state that goes beyond 50% RH, can you pull those out and store them somewhere else that you can regulate the RH better? Look at the light. Can you lower those light levels, both visible and UV light? When you're putting these plastics on display, treat them as sensitive objects so have them at a low light level as much as possible. And then ventilation also. You should fear that buildup of gases so don't store these plastics wrapped up. Ventilate as much as possible. Again, and if somebody recommends scavengers, or you come across an older article that talks about scavengers, again, things like zeolites or activated charcoal, the thought right now is to avoid them. So using standard blueboard or cryo boxes is actually a good default when it comes to storage with these things. And also support. How are these things being supported, both in storage and display? You can think of a lot of the plastic is going to be thermoplastic, which means they can bend and deform such few changes in temperature and so you want to fully support and remove stress as much as possible. If you have concern about a plastic weeping or changing over time and maybe becoming tacky, then maybe putting a silicone release mylar or something between the objects is going to be a wise thing to do. And I can't say it enough document. Get good written and photographic documentation of your plastics now. If you've got two-dimensional plastics, film, works of art, things like that, then you want to scan it and digitize it so that you save that information. And then again, maybe for some of these, you might be at the point of wanting to deaccession. And then here's all of that in one brief bullet-pointed slide against that when you're thinking about these things you can just walk through it. But observation is really important. And as we wrap up the last two slides, I just wanted to point out something two years ago, a multi-year project out of the European Union called Top Art. This is preservation of plastic, artifacts, and museum collections. And really this was a really good push to go beyond preventive. Most of what I talked about today was preventive conservation with plastics so thinking about the environment. And then the follow-up, we really got to push this and come up with an inner vent of conservation. How are we cleaning these things? How are we repairing plastics? And so there was a multi-year study again about how to do that. And there's so much information on the Top Art site that I really encourage you guys to explore that. Part of what came up was the cleaning study. And actually, let's take a moment and we'll do two of our last polls, which is, have you cleaned your plastics? And then if so, I'm curious about how you go about cleaning your plastics. The soft brush and vacuum seems to be in the lead for those who have cleaned plastics. That's good. Yes, there are varieties. It's interesting that everything is represented. And some people have done things that I haven't listed. All right, so yes, soft brush and vacuum is in the lead. It's good. So Pop Art, they did a study on soft brush and vacuum plastics. And it's always been art of fault in conservation to say, you know, when it comes to plastics, yes, soft brush and vacuum is probably the way to go. And what Pop Art's study found was that all the dry cleaning methods have scratched in some degree the plastics, except for compressed air. That said, because of the risk of solvent or wet cleaning, so if you're not a conservator, you shouldn't do that. So understanding that dry cleaning should still happen in many cases. If you do that, whatever method you're doing, they also studied how you're cleaning. So actually doing a straight path, which basically means you're just going to, like, put it down and rub and lift. You're not doing a circular, you know, sort of waxing motion. Doing that straight path motion, not back and forth, just one path, cause less scratch when it comes to dry cleaning. So that's something to keep in mind. From what they studied, they found that this list of materials actually was safer based on it scratched less to use the things listed on your screen. Now, you can go to that Pop Art website and sort of look at how they studied this and how they determined this, but I did want to share this now, realizing that in some collections, you know, we can't always say call a conservator because that's not always going to be practical. So if you are going to do dry cleaning, I want to see you do it safer. Know that there's a different list of materials if you have a conservator, they're going to do aqueous cleaning. So we should make sure that they're aware that there is a different list of materials to use for that. All right, so I have shared a lot of information. I know that Susan's been putting questions to the side, and we have about, you know, 15 to 20 minutes, I think, to dive in. So I'm going to let Susan guide the question. Okay, and before we start, I'm going to put up the evaluation link. The evaluations are really important, so please fill it out. And I'm also going to say, if we don't get to those questions, because there are a lot of them, I will give them to Mary, and she'll make written answers and I'll post them. It might not be, I might not be able to post them with the recording immediately, but I will let you know that I've posted them. So Lynn Sharp says, still wondering from the first slide, the concept natural plastics, I never heard of hoof as a plastic. So yes, the idea of a natural plastic is that you can use heat and moisture to form or shape those things. So horn, tortoiselle is considered natural plastic, because again, you can use heat and moisture to change them into shape. I was surprised that you didn't include rubber as a natural plastic. I always think of, I mean it is, I always think of in my mind, and this might just be me, I always think of rubber as its own thing. So it is, because it's a natural elastomer, but I feel like so many people have died into rubber and there's so much out there that I just tend not to group it in plastic, so that's just sort of my own mind I think. And I cut you off, you were going to say something about when you were at Winniture. Oh, just that there is a giant, beautiful tortoiselle bird cage. And so in my mind, I always picture they've made these tiny ribs out of tortoiselle and bent them into plates. So in my mind, that helps me think of how tortoiselle can be considered a natural plastic. Polly Huff says, what type of plastic or plastic like materials would you expect to encounter in the 1890-1910 time period collection? So that's things like the timeline and there's even more expansive timelines out there can help you. And so if you see what's available up until 1910, which that's the introduction of the faculty and work your way back, you're pretty limited on what's available. And so that information, combined with the form and the use of plastic, you can probably get a pretty tight idea of maybe two or three plastics it could be, maybe even one, based on, again, use, form, and time. Yeah. Okay. Emma Lang says, are plastics in paint, particular paints for marine uses and is there any way, are there any ways to help stabilize or to stay stable-ish, acknowledging inherent vice is everywhere in maritime collections? Sure. It certainly is. So, yes, there are plastics in paints and there is, especially in through painting literature, we'll probably dive into that more since painting is not my specialty. I don't have enough information to share and then when you get to maritime paints, that gets even more specific because, you know, you're going to choose a paint that is going to withstand salt and things like that. So there's probably, this is where it's helpful to go into the trade literature and figure out what your options are from that and then also make observations about how it's aging. So not an answer, Emma, and I'm sorry about that, but that's the best I have. Yeah. But looking at trade literature is really useful, especially if you can get period trade literature. Yeah. Dominic St. Victor says, do you have examples of hard rubber? So there were a few in the, like, two slides that gave you guys this hard rubber. They tend to be, hard rubber can be really dark and molded. They sometimes look like human case kind of ideas. And the thing, the only one I ever treated was a match case from the 1860s and it actually was off-guessing or reacting enough that it was corroding the metal pin. So if you have something of that time period, they tend to be dark, real Victorian looking materials, then that might be hard rubber. Right. And it's also called cow-chook. Degarotype cases were made out of it as were early toothbrushes and a lot of degarotype places, degarotypes were, cases were made at the Pro-Felactic Brush Company, which we now know is pro-brush. But that was one of the first plastic manufacturers in Florence, Massachusetts. Evelyn Fiddler says, can cellulose nitrate burst into flames spontaneously? That's always the thought in this year, especially with film collections, but really it has to get to a high enough temperature that you're going to reach that. So if you had a heavy load of film, you had a lot of it, and you say lost your HVAC and it was somewhere where you are and the temperature got very high, then yes, then yes, you can have a fire start. But you shouldn't, I've never heard of that happening with a three-dimensional cellulose nitrate object. But again, film, because there tends to be so much in the storage and temperature load, that you can have the fire that way. Another reason for low temperature. Susan? If you have movie film, it's much more likely to explode. But if you have cellulose nitrate negatives that are in envelopes, that's not nearly as dangerous, but when you have a big mass of cellulose nitrate wound in a can, that can go in any stage of deterioration. I once was in a nitrate fire. They're not fun. Oh, gosh. Yeah. Okay. Lee Stubbs-Lee says, Mary, we're currently planning a new museum facility and have earmarked two cool storage rooms for plastic materials. Can you point me to any good resources for determining the specs of what we need? If it's okay, let's flag that once so that I can poke around a bit. In my mind, I'm really sure there's some information coming from Australia about film storage. Yeah, it would be better if I could poke around. Okay. Evelyn also says, if you're so unstable, I'm not sure what we can be done to a recipe. Let's see. I copied her twice. Cindy Opitz says, what is memory foam made of? I don't know, but I sleep on it, so you think I would have looked that up, I know. Okay. So Polly Huff says, so for the toothbrush you just showed, what would have been the proper storage material? That's a cellulose nitride one that was on the metal. So it would be fascinating if, I wish I knew what it looked like when they did all that, because it could have been that they found it in pieces and that was a way to keep the pieces together. I have a feeling that the handle was probably more whole and they were scared of it deteriorating or crumbling the way it did. And so general rules of thumb, don't wrap up your plastic and plastic and metal don't do well together. So right off the bat there were two choices, good intention choices though, made that I would avoid. And so for that really, just making a custom blue board box and laying it in there, ventilating it that way, laying it on the blue board would have been, in my opinion, a better route. Diaz says, is there a preferred vendor to recommend for the test strips? I will add, I'll get that information from Mary and I'll add it to the handout. So know when the handout gets posted with the recording, it will be updated. So, because we have a lot of questions, I don't want to waste time on that. I mean, I'll get you the information, but I don't want to... Okay. Dana Netsville says, how can you ventilate plastic without affecting other items in your collection room? And that's the question, right? So this is where you can, I can say, ideally you would, you know your plastics and then store light plastics as light plastics and then, you know, vent that way. If that's not happening, then you sort of look in your situation and what are your storage cabinets? Do you even have vents on them? Okay, let's open them. If you're concerned about things nearby, which has happened to me in sort of a more open shelving situation where you had plastics on one side, back to back with beautiful metal scientific instruments on the other, and so my solution for that was to put mylar between those two units of shelves because mylar is actually a good physical barrier that will block the off-gassing. So you don't want to encase your objects in mylar because, again, that's just going to make them sort of sit in that off-gassing soup, but you can use that as a physical blocker for materials nearby. Okay. Emma Lang says, sorry if this is too specific. Our museum is directly on the Atlantic coast. Well, a bay, but it's, let's not split hairs, is salt in the air is something that will accelerate plastic deterioration. In particular, I'm thinking of our historic ships that are in the water. They have a lot of plastics on them, but I'm also sure that the air in our building is a bit salinated. I had not heard of anybody studying that, but Emma, I have to say, if you have an observation, particularly the things on the ship versus inside, that would be, I think, an interesting case study to explore and share if you're ever able to. But I have not heard of anything specifically or with a specific plastic, but that doesn't mean it's not true. I haven't come across it. Andrea Lange, Andrea Young says, what's the best way to store old toys like Barbie dolls and Star Wars figures? Great question. So if we make the assumption, this is where it gets tricky when it comes to toys, if we make the assumption of PVC, which, you know, with Barbies, especially early on, are, ideally those are going to be an idea of a non-absorbent container or something like glass. No, I have to admit that it would be kind of creepy to go into a toy collection or your own personal home with toys and then have Barbies just lying shelves and glass jars. You'd have a lot of explaining to do. But for the material itself, that does seem to be what is best. Yeah, PVC. Linda Schmitzferg says, what about storage and other concerns for CDs, DVDs made of polycarbonates? And there was a mention of a conservatgram on that topic, and I will add it to the handout. But what are your thoughts on that? You know, that is beyond my realm of expertise. So I would say I would read the conservatgram until ground because I'm not sure. Okay. Dominic Sendvictor says, what are your thoughts on polypropylene? I haven't. There could be some concerns with it, but I haven't come across too many issues to be honest. Okay. Jason Akin says, what about scavengers and exhibit cases? So if you're using, so it's a good question. It's hard to answer without specifics, right? And then he says, what about when you're displaying mixed natural and plastics in an exhibit case? I guess. Yeah. So then, you know, it's no pun intended, right? It's a case-by-case basis. So it's why are the scavengers there? And if the scavengers are there for fear of the plastics, then maybe you evaluate we don't need scavengers. If the scavengers are there for another reason, then you have to sort of weigh out, okay, what is that reason versus my potential risk? So plastic, ideally knowing what that type of plastic is. Okay. So again, just knowing that some scavengers are not good for some plastics, though. And Vicki Stone says, we use lots of plastics in housing materials, ethophome, choroplast, et cetera. Are those okay to continue to use? That's a really good question. That's a big one, right? Because we think so. And I'm sure we've all been in that situation that you see some of those materials that aren't doing well. And then another batch is really doing okay currently. Or even 10 years on, still seems to be stable. So we still think them as stable. But knowing that manufacturers can change recipes, knowing what they've been exposed to can change how those are going to age, all of that. Part of an effort to answer that is there's a materials working group that is formed as part of AIC to explore some of those issues, to get some information about that. So, you know, how do you inform with the audit test? How do you use site-slite cameo? How do you get information from manufacturers to help you inform those decisions? So again, this materials working group has formed to try to answer some of that. So in some ways, stay tuned, but also don't panic because we still think they're okay, but we'll see. Yeah, okay. We only have three more minutes, but there are three questions so we can do a minute each. Julia Merkel says, some of my archives colleagues love plastic clips instead of stainless steel paper clips. Can you give me a succinct reason why the plastic is a poor choice? My argument is that it distorts the paper and I don't trust the plastic not to off-gas. Biodeterioration cases on plastic. So I would do, I don't know if you've done this, but what I mean is to look online and try to Google what is the plastic that is on that paper clip because if it is something like PVC, you are well-armed to say that you shouldn't use it, but I don't know that specific plastic. I think for crimping paper and all of that, there's reasons not to use paper clips and ripping and tearing like that. So you might have a multi-prong of rationale to stop it, but I would do a Google search and see what you could find. Can you explain how to vent plastics and storage? Is it okay for them to be vented into the storage area or cabinet? Again, this sort of depends on the setup. Mostly if they're vented into the storage room, if it's large enough and things, it's probably okay unless it's overwhelmingly smelly. The other thing to think about is that a lot of times coming off of the plastic may be heavier than air so that if you can design your cabinet, you actually may want to vent towards the bottom rather than say the top of the cabinet or you may have to retrofit your cabinet, drilling holes, things like that if it's really that building up that much. And finally, Eileen van der Veldt says, or Eileen says, what's the difference between natural rubber and latex? They're the same. Are they the same? They're the same, yeah. Thank you, Susan. You're welcome. I've done far too much stuff on leather. I mean, on rubber. Yeah, let's see. I'm trying to see if there are any other questions. I'll look through here and see if there are any other questions that we missed, but it's time for us to go. Please remember to do the evaluation and we'll see you in a few weeks for packing and creating. Thank you so much, Mary. And thank you, Mike. And thank you, all of you who came. Okay, the audio stopped. Okay.