While you may be tempted to clean your coins to make them look shiny and new, proceed with caution. Most of the time, cleaning coins reduces their value. Believe it or not, older coins that show the deep coloration of age are far more desirable than coins whose surfaces have been stripped away by improper cleaning.
If you absolutely must clean a coin to remove dirt, use good-quality mild soap and water. Once you’ve washed the coin, pat it dry with a soft towel. Don’t brush or rub it, which can scratch the coin’s delicate surface.
Handling Your Collection
To preserve the value and natural condition of your coins, it is important that you handle them carefully.
- Hold a coin by its edges, between the thumb and forefinger. This protects the coin’s surface from fingerprints and the natural oils on your skin, which can be corrosive.
- Some experienced coin collectors wear soft cotton gloves when handling their uncirculated or proof coins. If you choose not to wear gloves, make sure your hands are clean before handling your coins.
- Hold coins over a soft towel or other soft surface in case you drop them.
- Don’t talk directly over your coins because tiny, almost invisible droplets of saliva can drop onto the coin and show up later as spots. Just like fingerprints, those marks are difficult, if not impossible, to remove.
Source: The above information was copied from the United States Mint website.