As you step into the world of ancient coin collecting
, you may acquire slightly dirty coins that will benefit from a good cleaning. Some coins are already beautiful examples of numismatic art, despite the need to expose details and inscriptions on their surfaces. Other coins
are heavily encrusted, and you can expect that they will need extensive cleaning for proper identification.
When it comes to cleaning ancient coins, it is important to be gentle and patient. The first coins that you clean should be your least valued. This will leave room for trial and error. There is no set procedure for cleaning ancient coins, as all coins vary in composition, age, and condition. It takes experimentation and practice to develop cleaning techniques. Within time, you will find a method that works best for you.
Small brushes are very useful cleaning tools. These brushes are found at hobby shops, and numismatic supply stores. Brushes with bristles made of plastic, brass, and steel are recommended. Brass bristles are rather versatile, because they are more stiff than plastic, and less abrasive than steel. A Brass brush provides a good middle ground.
While you carry out the detail work involved in cleaning, never apply a metal tool directly to the surface of a coin that is composed of a softer metal. This can result in scratches, and even deeper damage. If you use a steel brush, only use it to remove the outer-most layers of dirt from a coin. Whenever possible, use plastic tools.
Brushes designed for hobbyists are worth the investment, but there are other useful miscellaneous items that can help you, as well. Toothpicks, sharpened bamboo, straight pins, toothbrushes, dental tools, and art gum erasers make good cleaning tools. You may already have some of these, so take a look around your home.
The first step to cleaning a coin is to soak it water. This will loosen deposits and encrustations, making them easier to remove. Use distilled water, as tap water can expose your coin to harmful dissolved minerals. Let your coin soak for a day or so, remove it, and brush it lightly. You may have to repeat this process over the span of days, or weeks, depending on how dirty the coin is. After you soak a coin, always dry it thoroughly.
If distilled water does not give you the results that you want, try soaking your coin in olive oil. Place the coin in a sealed container made of plastic or glass. Leave it for a week, check the condition of the dirt, and repeat the process. This can take anywhere from a week, to months to complete. After removing the coin from the olive oil, you will need to get all of the oil off of the coin’s surface. To accomplish this, use a gentle, non-detergent degreaser.
For those that want faster results, there are a number of chemical cleaners available for metals. The beginner should use these cleaners with caution, as all coins are different. Chemical reactions can be rather unpredictable, so experiment with your less valuable coins, first. Always study the usage label of a chemical cleaner to make sure that it is compatible with the composition of your coin.
When you are satisfied with the condition of a coin after cleaning, you may want to seal it for protection. Apply a sealer, wax polish, or a clear acrylic finish. Use products that are specified for use during restoration, and again, always check the usage label for compatibility.
Remember that it is always more desirable to preserve a coin’s patina than it is to damage or remove it during cleaning. If you are new to cleaning coins, and you have a coin that may be very valuable, take it to a coin restoration professional.