If you are a coin collector or simply someone who would prefer to carry clean as opposed to dirty coins, there are methods to clean silver, gold and copper coins. However, sometimes you may not want to clean the coins at all. Before you attempt to clean a coin you should know its value. If you don’t know its worth, don’t clean it. If you think it’s valuable or know it's valuable, don’t clean it. Leave the coin untouched and put it in a coin holder. Coin collectors and dealers like to purchase coins in their original condition, dirt and all.
What Not to Do
Do not clean your coins with metal polishes, silver tarnish remover or commercial jewelry cleaners. Silver tarnish removers will remove the tone that accumulates over time on silver and copper coins; when this is removed, scratches, pockmarks and small spots can pop up, which make the coin less valuable. In fact, the value can be lowered by as much as 90 percent if you clean a valuable coin in this fashion because dealers and collectors won’t buy coins that have been improperly cleaned.
What to Do
Take your coins to a professional who knows how to properly clean coins using a method called dripping. When you are handling your coins, touch the edges only to avoid getting your fingerprints on the surface. If your coins are terribly corroded and you can’t see the date or other details, ask a professional if you should proceed with cleaning.
Silver coins turn black to brown over time or sometimes dull gray. Silver can acquire a green, violet or blue tone when the coin is tarnished. Do not clean a coin that has turned this color. If the coin is too tarnished to see details, do not use an abrasive cloth or paste on it. Clean dark silver coins using rubbing alcohol, polish remover that contains acetone, ammonia, lemon juice or vinegar. Put the coin or coins in a container filled with one of these ingredients and let it soak until encrustations and dirt have been dislodged, recommends Mycoincollecting.com. Pat the coin dry or allow it to air-dry. Don’t polish or rub it because this can scratch the surface and can remove metal from the surface.
Gold coins can be cleaned by washing them in warm, soapy distilled water, using a soft cotton washcloth of a soft toothbrush. Gold is softer than silver so you have to be very careful when cleaning gold.
Copper is chemically active. A new copper coin is brilliant orange but eventually turns brown. Cleaning a copper coin can make it look worse. Soak the copper coin in grape oil or olive oil. The coin will have to soak for up to four days, and sometimes it may take weeks to work. Maintain the appearance of your copper coins by stroking them with a soft camel’s hairbrush a couple of times a year.
You can also use MS70 to clean copper coins. Wear gloves because it will dry out your skin if it makes contact. Let the coin soak in the MS70 and then neutralize the MS70 by adding baking soda and warm water over the coin. Dry the coat and apply Blue Ribbon coin cleaner to it. Let it dry for a few days and then white off any excess using a cotton ball. Store properly.
Consider other cleaning techniques offered by collectors, including rubbing a penny with a pencil eraser. Rubbing ketchup onto a penny using a toothbrush may clean the coin. Making a paste out of baking soda and water and rubbing the paste onto the penny can work. Another technique for cleaning pennies involves combining vinegar and salt in a bowl and adding your dirty pennies to the mixture; or, toss your dirty pennies into a combination of lemon and salt.