 Dear Steve, how can I get a scratch out of my CRT screen? Can you please explain the protective lens on a CRT? Absolutely. Cathode ray tubes are made of glass and thus they're very susceptible to scratches and other damage on the screen. This is especially a problem when it came to the highest-end broadcast CRT monitors. You see big Hollywood companies like Warner Brothers or Fox wouldn't actually own a lot of these monitors or really lots of broadcast equipment in general. Movie studios would rent or lease these machines from companies that own and stored large amounts of broadcasts, television and film editing equipment, including high-end CRTs. Then each individual film or TV show would have its own budget for the cost to rent a studio space and to rent a certain number of BVMs or other high-end equipment they may need to edit their program. This equipment would have otherwise cost the studios hundreds of thousands of dollars to purchase outright. They would have had additional cost to maintain and store the equipment, as where rental companies stepped in. For a fee you could have the equipment brought to a studio or really wherever you were shooting a movie or TV show. The rental company would bring the equipment, set it up and even have services available while the customer was using the equipment. This equipment needed to be routinely serviced and repaired in the field by technicians like the legendary Savon Pat for Sony. One of the problems with renting this equipment is you have to move it around a lot. We all know that CRTs are heavy and broadcast quality monitors were exceptionally heavy, weighing up to 80 pounds for a single 14-inch Sony BVM. This meant that at many times minimum wage employees would have been moving around expensive CRTs without any real care for the condition along the way. I mean, they were looking around huge CRTs all day. That would have been a tough job in itself. Equipment rental and leasing companies had a costly problem on their hands as CRTs would regularly become scratched on the front screens. Thankfully Sony engineered a solution for their highest-ed PVMs and BVM CRTs. They added an anti-glare clear layer to the front screen of the CRT. This layer would act as both a measure to reduce the glare reflecting off the glass and provide a protective lens that could be removed if it was damaged. This protective lens could be removed if the screen was dinged or scratched with very imitable impact on the screen's picture quality. Unfortunately, Sony only added this lens to most of their broadcast video monitor CRTs and a couple of PVMs. The L5 series has the protective layer and some of the 20M4 and 20M4 used will also have the lens. All other medical-grade CRTs and lower-end PVMs, however, will not have the anti-glare lens. These CRT screens have nothing between you and the glass. That means that if a medical-grade PVM has a scratch on the screen, then it's most likely permanent. It's not all bad, though. You can easily and safely clean any CRT screen that doesn't have a lens with nearly any type of cleaner, like Windex, for example. However, you have to be extremely careful when cleaning the surface of a CRT with an anti-glare lens. Ammonia and other chemicals can cause damage to the lens in the CRT. It's best to try to clean the surfaces with a wet soft towel, using only water if possible, or a very diluted mix of cleaner if you really need it, and get it off the lens as quickly as possible. This lens has helped save many CRT tubes from otherwise being scratched, chipped, and ruined. So now you know why lenses were made and what you can do if you have damage on a lens. But there also may be other brands and manufacturers in the 2000s that introduced anti-glare lenses to their CRT tubes. I'm also not certain how many other CRTs that were consumer-level televisions have some type of lens to them. But if you know any, please list them in the comments below. Thanks again for watching everybody, and I'll see you guys next time with some more retro content.