The first rule of coin collecting is: DO NOT CLEAN YOUR COINS. This is the most important piece of advice for any collector, new or old. Serious collectors and experts agree that most coins should ...

You know those pennies, nickels, dimes, and quarters in your wallet have been passed around a lot. And that means they’re probably pretty grimy. You’ve probably accidentally washed a few forgotten ...

Copper is found in many household items, such as jewelry, bowls, pots, and utensils. Over time, though, the surrounding air causes the metal to develop a layer of copper oxide, which makes it look ...