Of course, if you wish to clean coins for your own collection, there are a few options available to you. The most obvious one - rubbing or using abrasives - is something you should not do, however. Metal polishes put little scratches on the surface of the coin and remove little bits of gold. No one desires a polished, scratched coin. Be cautious wiping your coins dry after cleaning, too. Gold is very soft, and even a cloth that looks non abrasive can leave small scratches. Dab coins dry after cleaning, or use an air blower, instead.

Dirty gold coins can be cleaned safely using gentle detergents or soap and a small amount of water. Some people will use a bit of soap in a bowl of water and boil the coins gently over a hot burner until they're clean. This is better for big lots. Never let the pan boil dry, however. Your beautiful gold coins will turn black! If you have access to an ultrasonic tank, you can use it to vibrate your coins in a cleaning solution and remove dirt, instead.

To take off stains, you'll have to think about what caused them. Many stains will come off with acetone (nail polish remover), which also takes off the residues from coins being taped together. If you use a solvent, be sure to do it in a well ventilated area. Once you've removed stains, you'll want to avoid sticking anything to your coins.

For rust stains, caused by coins that have been kept in contact with rusty iron or steel, use a weak acid. Soda, lemon juice and vinegar all work very well for this purpose. Rinse your coin afterward to get any sticky residue off. Persistent rust stains can be removed with more concentrated or stronger acids.

If you have a proof coin, with a highly polished surface, you need to be extra cautious. Nearly any contact can cause problems with the beauty of these rare coins. You must avoid rubbing at all costs, and dry these coins careful. Don't touch these coins with bare fingers, either. You'll leave a fingerprint that will ruin the shine. For many of us, gold proof coins are something that should be restored by professionals, as are many other gold coins. Think hard about whether yours need cleaning, and if they do, be careful!