 Is there anything worse than dirty pennies? You'd like to count your coins and have them all shiny and new, but no matter how hard you try to clean them, you just can't get them sparkling. Baking. Scrubbing. Licking. There's no use. You might as well just throw them out. But wait! There is something that can help save the day. Science! Science has been known to solve a lot of life's problems, and now it's helping fix the blight of dirty pennies. All you need is a bowl, some acid, and some salt. Worried you won't have enough acid? Well, don't! This science even works with ketchup. Just pour the salt into the bowl, add the vinegar, and start adding those pennies. Then, leave them to soak for five minutes. You can watch if you want to. After the five minutes has passed, remove the pennies, give them a rinse, and then a rub to dry them off. Look at those sparkling queen pennies. Science success! Here's how it works. Pennies look dirty because a coating of copper oxide made from the copper and the penny reacting with the air forms over time. When the penny is dipped in an acid, the acid reacts with the copper oxide and removes it from the surface. The salt helps to increase the strength of the acid, speeding up the reaction. You have to rinse the pennies after cleaning to ensure no further reactions take place. So now you'll never have to spend a dirty penny again. Thanks, Science!