Another big problem with using chemicals to clean coins is that once a reaction with the metal is begun by using a chemical on it, it is sometimes almost impossible to stop it, and there are well recorded incidents of accelerated corrosion in chemically treated ancient metal. This means that a year later the coins are in worse shape than before cleaning. Not a pretty sight.

The primary method for cleaning almost anything is soaking in water. For ancient metals its best if the water be as free of additives, like chlorine, as possible. Simply boiling water helps remove a percentage of its added chemicals.

Water is the most effective solvent on the planet Earth. Thats simply because there is so much of it, and its liquidity is assured within a fairly broad spectrum of temperature. Everything alive depends on the diffusivity effects of water on solids to live. Soaking your coins in water does not hurt them, provided the water is relatively free of chemicals, and tap water is usually OK, although watch for sulphur and silver!  They do not mix well at all. The longer coins soak, the more encrusted dirt will be loosened. That is the name of this game.

The problem with soaking is that to be effective the metal must be soaked long enough to penetrate to the metal core of the coin. On the average this takes several years. If the coins are soaked in anything, and only partially permeated with the water, any picking or brushing will have adverse effects. There are many coins that were only partially soaked, then brushed, so that the outer edges came clean long before the center of the coin, because of the increased angle of the brush at the edge. By the time the center of the coin becomes clean, the edges of the coin have been worn nearly flat with all the brushing. This totally detracts from the items value and can easily be categorized under the heading of Destruction.

There are many recommendations for coin cleaning that entail soaking in oil. This is risky business, and may introduce chemicals to the metal that are not good for it. Soaking in oil will not accomplish anything that soaking in water does not, and it adds the problem of removing the oil if that becomes necessary during further steps of restoration. Oils can sometimes be removed with detergents, but again, that means more chemicals to upset what has become, over 2000 or so years, a rather tenuous chemical balance. It is our suggestion that water be used in lieu of oil, and that you preclude all use of any oils in treating your coins except perhaps for some very esoteric circumstances during the finishing process. Olive oil in particular is extremely acidic, and etches ancient bronze destructively.

One commonality among novice collectors seems to be the attempt to clean metal by "Shining" it with chemical preparations. Many acids have been tried with only varying degrees of success, and they are usually quite dangerous, and are very hard to control. Many times a secondary chemical needs to be used to halt or nullify a chemical process begun with acids. Most chemicals used to clean coins are very carcinogenic. There is a silver dip that is used by professional conservators, people who meticulously preserve old plated serving sets and the like, and this dip is called acidified thioreau. It chemically dissolves silver sulfide. It is highly carcinogenic although it is sometimes sold in grocery stores as silver cleaner. The amount of rinsing needed to halt the reaction created by this treatment prohibits its use on many things, and its a pretty sure thing that the average person attempting preservation will hurt themselves, and the things they are trying to clean, with chemicals like this.

I have even heard of people using things like drano and other chemically hostile agents on old metal, though I haven't heard a lot of happy reports from those quarters. Electronic Cleaning is another magnitude of efficiency, at least for the restorer of ancient numismatics, which of course is the basis of this portrayal.

Be advised that almost all chemical cleaners are hazardous. Disposal is a real problem and is the Responsibility of the purchaser. Use only with extreme caution and foreknowledge, and have adequate safe disposal prepared for the spent chemicals. We recommend no chemicals for cleaning of ancient metals, and go so far as to suggest they be shunned completely.

Picks and Brushes

The most important of the mechanical cleaning processes are the use of picks and brushes. The use of picks and brushes, with the emphasis on Picks, is what sets the restorer away from the novice. Conservation of ancient metal is Care to Detail. Meticulousness.  This is made easier with electronic cleaning methods, and the two fit together like hand and glove.

A pick is usually a pencil shaped piece of wood or plastic, with a rounded point on the ends. Occasionally a sharper point is warranted, and most picks are easily sharpened with a knife, pencil sharpener or by grinding on pavement.

Another common shape for a cleaning pick is the spatula shape,where one end of the pick is flattened. Imagine a worn regular screwdriver head, but plastic. Round pointed picks reach the places that spatula ended picks cannot, and very Pointed picks are only for hard-to-get places on the coin, like between designs or letters, or around the edges. Plastic picks are easy to obtain and are very inexpensive. Many can be culled from junk bins at thrift stores. The best are made from a hard type of plastic, which is still somewhat flexible. Good plastic picks wear from abrasion on the coins, and will need to be replaced regularly as they wear and are sharpened.

You will get to know the better plastics for coin cleaning by experimenting with as many different types as you can lay hands on. This is easy and inexpensive to do. Any somewhat flexible and hard plastic that will wear against the metal makes a good plastic pick. Nylon knitting needles offer the coin conservator interesting possibilities, as do certain pieces of barware used for stirring drinks.

The classic numismatic cleaning pick is bamboo. Bamboo has been used for this purpose for years. Bamboo skewers that work perfectly for ancient coin and metal cleaning can be purchased at any hardware or grocery store. Chopstix make great bamboo picks also, and are of greater size and strength than bamboo skewers. Bamboo is excellent because as it wears it develops somewhat of a "Mop" tip meaning the end/tip becomes squished out, and retains water well, which is a good thing.

When using plastic or wooden picks on a coins surface always keep the surface you are working on wet. This can be accomplished by dipping the pick in water and transferring water in drops to the surface of the coin. You want a wet slurry on the coins face while you are working; the wetness will decrease the chance of scratching the coin with an adherence on the end of your pick.

Easy Does It when using picks to clean coins. You can damage coins with picks too, and its a fine line, which basically depends on the material of the pick, and the make-up of the coins surface. Many times strenuous force is needed to get real hard corrosions to pop off, but there are some coins which are "Mushy", and when that type of strenuous force is applied, the surface actually becomes deformed. Thankfully this doesn't happen much. Fingernails and skin are quite a lot softer than metal, and can be used effectively in some cleaning processes, to good result.

When cleaning with picks use a back and forth, or circular motion, lightly at first, and only increasing force where needed. Again, nine times out of ten you will want to keep the artifacts surface wet. There are two basic ways to hold a cleaning pick. One is choked up, with fingers down near the point...this gives you a lot of control and energy down at the point...the second way of holding the pick is out near the end...this comes in handy under certain circumstance when a spring kind of action-energy is required to remove small and tenacious objects of encrustation.

All this brings us to another method, or sub-method of using picks to clean coinage. The function of leverage in the use of picks to clean coins is a circumstance with a lot of variety, and needs to be studied and experimented with. Many times the coin is put on its edge, while forceful downward movement is applied to the tip of the pick. This tends to pop encrustations off en masse, and can be used to penetrate deep detail, although this can damage coins which are mushy or cracked. Forward pushing motions of the pick, on a coin lying on its surface, are another form of leverage, and can be used effectively in many instances.

After initial cleaning with the picks, further rinsing can take place, and brushes, even an old toothbrush will do, will further aid the final removal of grime and encrustation. Brushes are not recommended for most cleaning but are very good to have around when they are needed. Brushing is most advantageous after picking of the metals surface is completed, or near complete.

Picking is, for the most part, the largest of the cleaning process.  It is recommended that all corrosions be removed by picking and brushing before the coin is finished. If corrosions are left on the coin they will eventually begin their chemical processes again, and spread; and as has already been mentioned, its even possible that they will be accelerated, if they are not entirely removed from the coin. Much of this process will become clearer to you, dear reader, as you progress through the next chapters.    It would be best if you read this in its entirety, twice even, before beginning your experiments.

Tumbling and Polishing