Ancient Coin Cleaning
Ancient coin cleaning can be an extremely rewarding hobby. Slowly taking off the dirt that has accumulated over the centuries and revealing what lies beneath can be exciting and give a collector a true sense of accomplishment. Just let your imagination run wild. Ask yourself where, when, who, why and try too trace the history of the coin. There are a lot of great sites to help you identify your coins. Wildwinds.com and Forvm ancient coins are two of the best. There is also a wide range of books available.
The tools you will need: A stiff bristle brush (plastic or fibreglass), toothpicks or bamboo skewers, soft brass brush, straight pins, metal picks, Q-tips, clean rags, glass or plastic containers, a good light, a magnifying glass (a stereo microscope is the best but is expensive). I use a gooseneck lamp with a built in magnifier, they are fairly cheap to buy.
There are several cleaning methods that are widely used.
Soap and Water
Place several coins into a container with enough soap and water to cover them completely. Swirl them are gently so not to damage the coins. Empty the dirty water out and rinse thoroughly to make sure all the soap residues is off the coins. Dry coins completely and check to see if you need to try again or if after several attempts you may need to move on to a different method. This method only works well to remove a light layer of dirt.
Distilled Water: Distilled water is used because it has no minerals that will harm the coins and is cheap to buy at any store. Allow coins to soak in distilled water for several hours or even better days. Make sure coins do not overlap each other in the containers. Check your coins, brush with a bristle brush (plastic or fibreglass). A hard toothbrush or denture brush will work great. Rinse and dry coins. If details still are not showing return coins to container with fresh distilled water, let soak again and repeat process. Some coins will clean up quickly while other will seem too take forever. You need to be patient as the reward of a good coin always makes up for everything.
After most of the dirt has been removed it is time to work on the fine details. Getting dirt out from in-between letters and other areas require other tools.
Small areas can be cleaned with a good light, steady hands and a variety of tools.
Sharpened bamboo skewers, or toothpicks work great, as they are gentle on the surface of the coin. Straight pins, metal picks etc. must be used with great care as to not scratch the coin. A brass pick is better and there is less chance of damage. This is where a stereomicroscope can be handy with really seeing the details.
Olive Oil: Olive oil is used in place of distilled water but the steps are the same, the only other thing that needs to be done is that to remove the olive oil from the coin(s) you will need to soak them in TSP(Tri-Sodium Phosphate) a cleaner available in most hardware stores. Soak coins in TSP and warm water for about 10 minutes and then rinse coin(s) completely to rid them of any TSP residue.
Glue Gun: You need the type of glue gun that uses glue sticks. This method can be risky as it may lift any silvering the coin has and may expose pit in the coin. Put a blob of glue on coin, let cool completely and then remove it. The glue will remove some of the dirt with it. You may have to repeat this several times.
Electrolysis Coin Cleaning: Many people use this method on the most stubborn coins (crusties) or when they do not have the patience to clean using the other methods. The draw back is that usually you remove the patina along with the dirt. The plans to build and instructions on how too use an electrolysis unit can be found by searching the web. All the parts are easy to come by or complete units can be purchase from some dealers or on eBay.
It is always a good idea to buy cheap low quality coins at the beginning and practice cleaning before moving on to the better quality ore expensive coins. Many people ignore the small coins, but careful cleaning of these can reveal some very interesting and beautiful coins. Remember it always better to leave the patina on a coin. It took centuries for it too develop on the coins surface and can help protect it. May coins lose value when the patina is removed.
Only clean a coin to the point that you find it attractive, not all the dirt has to be removed and most of all do not make a job of it, ENJOY the thrill of uncovering a piece of history.