Don't Clean Valuable Coins
Though your first reaction might be to clean and scrub every coin in your collection until it looks brand new, you should generally avoid cleaning coins unless:
- You know for certain that the coins are not valuable, or
- You don't care if the coins are valuable
Like all collectibles, cleaning anything that may potentially be valuable is best left to professionals. Cleaning to preserve value and avoid further damage takes great care and an understanding of the type of metal in the coin and the type of stain/blemish/coating that is affecting it. If you have coins that you would like to get professionally cleaned, talk to a local coin shop and see if they offer cleaning services or can recommend a local, respectable cleaning service (they may have one they use for the coins in their shop).
Cleaning Up Your Non-Valuable Coins
You could write a book on all the different ways to clean different types of coin problems. I'm going to cover a couple of different cleaning methods I've used, but they are by no means the only ways to deal with dirty coins. Do not use any of these cleaning methods on valuable coins, or coins made of silver or gold!
For a mild cleansing to remove loose dirt and surface oil, you can start with simple soap and water. Fill a bowl with water, add a squirt of liquid hand soap and mix it together. Take one or two handfuls of coins and swish them around in the bowl for about a minute. Take them out, rinse them with plain water, and immediately dry them with a towel - if any water drops are left to dry on the coins themselves, they could create new stains. Repeat with the rest of your coins.
If there is stuck-on dirt or grime, you can try to scrape it off with a pencil eraser or toothpick. You don't want to use anything that's harder than the metal you're cleaning, or you could cause new scratches. Toothpicks are especially handy for clearing dirt out of corners, letters, or other small designs in a coin.
|Before (left) and after (right)|
|Before (left) and after (right)|
There are many different cleaning solutions that you can buy online or from a coin shop that are designed for cleaning coins. Ask your coin shop for a product that they recommend, or do some searches online to see what other coin collectors like or don't like.
Once you've cleaned your coins, you need to handle them as little as possible to keep them clean. Hold cleaned coins only by the edges so that your fingers don't touch the front or back. You can use soft cotton gloves to handle coins once they've been cleaned (and it's not a bad idea to use them anytime you handle coins) to avoid transferring finger oil onto the coins. Seal your coins in paper or plastic flips so that they won't be exposed to more fingerprints or dust, and then store them in your chosen container (see my earlier post about starting a coin collection for more information about flips, albums, and boxes).
To Clean or Not To Clean?
Unless you are preparing coins for a gift or display, I feel that you're usually better off not cleaning your coins. The benefit you get from cleaning is very small, and you run the risk of reducing whatever value the coin might have. There is no doubt that a good cleaning can make a coin look significantly better, but authenticity often trumps appearance for collectibles - leaving your coins unaltered is usually the safest choice.