Cleaning Roman Coins

Collecting of ancient coins is a very beautiful hobby. The largest problem, or better, the largest challenge is their cleaning. Many guidances were already published. I also would like to communicate my experiences, which I've collected during years, to other collectors.

With the acquisition of ancient coins there are two different preservation degrees: On the one hand uncleaned coins with earth adhering, on the other hand coins, which already experienced a cleaning and/or a first preservation. Uncleaned coins are coloured by yellow, brown and green, conserved coins are dark to black.

I would like to begin with the uncleaned coins. A find coin is covered with different strongly adhering earth remainders. The damper a soil is, the more adhering is at the individual coin. For example a coin originating from England is more strongly decrepit than one from Italy. With these different find conditions there are naturally also different cleaning techniques. Now my experiences:

The coin, which we purchased, is many hundred years old, accordingly difficult can the removing of the dirt layer be. Our aim consists of shifting the coin as far as possible into the original state. We may not damage the coin however. We often need a calm hand, patience and perseverance. I've already experienced that coins regained their beauty not until after a half year. If we have the two characteristics patience and perseverance, we will enjoy much this hobby. It is fascinating to give the beauty back to coins, which were many hundreds of years ago in the circulation.

Many different tools and techniques were already tried out with larger or inferior success. I I'll enumerate the most important in the following. The basic tools are tweezers with coated points (you can find in the specialized trade), a strong magnifying glass (at least 8-10 dioptrin), a strong source of light, a tooth pick, a cotton or a linen rag, plastic containers of different sizes and finally a bottle olive oil.

The acquired coins are cleaned carefully of the roughest contamination in the dry condition with a tooth pick as the first step. The coin lies thereby on a folded cotton rag. The advantage is that the coin does not slip away, and can't get damaged. The dust and the grains of sand are to be removed regularly.

After these first cleaning we use the olive oil. Olive oil has the characteristic that it conserves the coin from the inside and cleans at the same time, because it is weakly acid. The coin has released now from its dirty layer (soil crust). An oil bath has various advantages. By the purely mechanical cleaning without employment of olive oil the coin can decompose gradually by air effect. An oil bath works strongly against the decomposition, by forming a kind of shield. It penetrates even into the finest pores and unfolds there its effect. For the oil bath I use small plastic containers, in each case are put about 50 coins in the oil. Within 24 hours, the coins full-sucked themselves with oil (' no small air vesicles rises any more). Now we can make the first wet cleaning.

With the tweezers we take the coin from the oil bath, let them drip off briefly and dab them off with a rag (not rubbing!) Afterwards we carefully scrape off the remaining dirt again with a tooth pick.

There are people, who work with steel needles or similar materials. That is exclusively suitable for professionals with calm hand and appropriate technical equipment. Later more.

After this cleaning passage we put the coin again into the oil bath. There it remains for approx. 2-3 days. Afterwards you have to repeat the cleaning procedure with the tooth pick which is described above. We should change the tooth pick regularly, because the effect diminishes with a blunt point. This cleaning procedure repeats itself so often, until the coin corresponds to our conceptions. In this time
we extend the period of the oil bath gradually (up to one week). If the oil reached a greenish, bluish or turquoise colouring, it is time to change the oil.

Following is to be said to the workplace: Because we need both hands for cleaning, it is of great advantage to use an enough large magnifying glass which leaves us the necessary place for working and possesses its own source of light. The specialized trade (in Europe) offers beautiful articles of "Eschenbach" for setting up as well as devices with mobile arms for screwing onto the table. The size of the magnifying glass should
amount at least 10cm and have at least 8-10 Dioptrin. Bigger is better, but unfortunately also more expensive. A small magnifying glass with 10-20 Dioptrin does good services for the most exact recognition of dirt remainders or for the determination of the coin.

Now I'll tell you about the coins already prepurified (= already a bit cleaned). In principle it's the same procedure as I've described already above. But you have to do an examination of dirty remainders with a magnifying glass before the cleaning. These are not so easily to find because the oil, with which these coins were already treated, has coloured dark the dirt adhering AND the coins.

After a thorough training period we can change our techniques and we can turn into making the cleaning with a steel needle. I made good experience with retired dentist tools (e.g. tiny putty and curved needle tips). Almost each dentist has retired tools (which are usually collected for the Third world). Just inquire your dentist. For finer work I take needles of sewing machines, these am strengthened and
thicker at the point. Further they are shorter than other steel needles and so they can be handled well. Of course, also the best tool wears out sometime. The point becomes blunt and we don't reach the fine grooves any more. Instead of replacing the tools, linked closely with a burdening of my wallet, I've turned over to sharpen the points with a hand drill with sharpening essay. It will be worthwhile if you clean many coins.

By the way: "Dremel" has extremely appropriate devices. I would like to underline again that the cleaning with such tools requires a calm hand, a good knowledge of ancient coins as well as a certain measure of experience of the coin cleaning. One gaffe can destroy the whole work. The needle cleaning isn't simple too. While we gain more experience, we becomes better.

To decrease the risk to destroy a coin it is advisable to clean the coin only briefly and carefully between long oil baths. In this way we need more time, until the coin is completely cleaned. It is nevertheless worthwhile, above all with better coins. The longer the coin is in the oil, the better can the dirt layer be separated.

After the first cleaning procedure, there are also different kinds of last dirt adherings, called patina. The patina can be black, lightgreen or white. This colouring comes from minerals. The more minerals in soil and the damper the soil is, the thicker is the coin surrounding crust. It's the last dirt layer on the coin. You must know by yourself, whether you want to bear the effort to clean these coins. It is possible in most cases, but time-consuming. Many collectors (me also) claim that you mustn't remove this layer. The most important reason: The authenticity of the coin can only be examined by the patina.

The proceeding of removing the patina: We scratch carefully some places of the uppermost layer with the needle. In that way develop tiny surface injuries, into which the oil can penetrate. The dirt layer separates beside of these places. This work must be repeated often, until we achieve our aim. I possess coins, which are already a half year in work.

I would like to tell you about the widespread rumour, that ultrasonic receivers are cleaning miracles. I made the experience that an ultrasonic cleaner is suitable for the first cleaning. Earth adherings are quite well removed. But that's all, it is impossible to have success with the next cleanings.

Special Case: "Sand Patina"
Antique coins from regions in Southern Europe with a mediterran climate often have a so-called "Sand Patina". Many cleaning techniques are not suitable for these coins. You should never put them into olive oil, because the attractive contrast effect would disappear. You can see this contrast effect on the pictures. You shouldn't clean them by chemicals or electrolysis too. The best way is to remove the dirt on the uppermost areas with a skalpel. Deep places like between the drapery or in eyes and the ear shouldn't be cleaned in order to preserve the contrast effect.

So, we took much time for the cleaning. Now we've some cleaned coins lying before us. With the identification we finish the procedure. For Roman coins there are a few very good, although quite expensive books (e.g. "Kankelfitz", "Mommsen"). Very goof is also this website: www.wildwinds.com/coins/ric. I can also recommend the purchase of used auction catalogs (e.g. on eBay), there are shown many different coins with a description and designation. I have more than hundred of them. Meanwhile I can determine each second antiquity coin with them.

I hope that I could help you with my experiences and tips and I wish you much success with cleaning!

In the following lines you find some interesting links for the identification and cleaning for Roman coins.

http://www.wildwinds.com/coins/ric/
Top-Link to identify the Roman coins

Cleaning:
http://www.cbnoble.com/clean.htm

http://vcrc.austincollege.edu/
Virtual catalogue of Roman Coins, general informations.

http://mywebpages.comcast.net/dougsmit/
An incredible resource for ancient coins lovers!

http://romancoins.info
Gallery of Roman coins.

http://www.oldromancoins.com/books1.htm
books

You'll find more links HERE!

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