Products
Several kinds of products can be used to clean coins. For copper coins, salt and vinegar, ketchup, lemon juice, Tabasco sauce or a copper cleaner will remove dirt. Baking soda or silver cleaners remove grime from silver coins. Nickel or gold coins can be cleaned with ammonia or in warm, soapy water.
Method
Coin cleaning begins with washing gently with soapy water and scrubbing with a soft, nylon brush. After removing the surface dirt, soak coins in a material designed to remove grime off the metal from which the coin is made. Keep the coins in the liquid for several hours or days until all the grime has been lifted.
Warning
Sometimes, cleaning a coin will lessen its value, as it reduces the authenticity of the coin in the eyes of some some collectors. Cleaning can erode the coin's original color and tone. If you are concerned about protecting the value of the coin, clean it with water only.