What newbies need to know: Cleaning Coins

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   Howdy everybody. I'm a long time Collectors' Universe forum poster and a while back I was asked by a member here if it was cool with me if he reposted something I had written over there. He also asked me to come over and check the place out. I don't know why it took me this long, but here I am.

At any rate, I don't know if the item in question was in fact posted here or not, so I will do so now. I hope it helps somebody.

Recently I�ve noticed a good number of new members to the forum that have questions about various topics of numismatic interest. Often times when these questions are posted the results are not what a newbie might be hoping for (mainly because people new to the hobby don�t always know how to ask exactly what they want to know). There are also �this question has been asked and answered a million times� and �this person is a troll� responses to deal with. In the interest of helping these new folks out I�ve decided to cover some basic information that may make their participation in these forums more enjoyable.

CLEANING COINS

Let me start by saying that most forum members (myself included) are generally against cleaning coins. While it�s none of our business what somebody chooses to with or to coins that they own the fact is that this person will not own the coins in question forever. The more people attempt to �improve� coins and fail the less original examples of those coins collectors at large will have to draw from. I believe that this idea is the fundamental reason so many people involved in numismatics are so strongly against the practice of cleaning coins.

With all of that said, the truth remains that some folks are going to insist on cleaning coins no matter what the popular opinion of the practice is. On top of that the experience gained from cleaning a few low value coins as an experiment can greatly enrich your understanding and enjoyment of this hobby (primarily by helping you identify coins that have been fooled with so you don�t blow good money on them). Because of all of this I have decided to lay out some basics about cleaning coins as I understand them.

1) VALUE AND RARITY If the coin you are considering �improving� is valuable (worth more money than you�d generally be comfortable throwing on a big bon fire) or rare do yourself and the rest of the numismatic world a big favor and leave it alone. Aside from the fact that attempts to clean a coin rarely end up as planned and often result in damage you may find that as you learn more about the hobby in general your tastes may change. After a few years of collecting I look at some coins in my collection that I once thought were unattractive as my best pieces. I�ve come to appreciate originality over bright and shiny, but then that is my perception and opinion, not necessarily yours.

2) DO NO HARM If you�ve decided you�re going to clean a coin make certain that the method you will use is as gentle as possible. Manual tools (tooth picks, rose thorns, exacto knives and so on) pose a big risk as it is very easy to scratch a coin with them. Chemical dips function by removing a thin layer of metal from the surface of your coin. Rubbing a coin (even ever so gently) with anything (your thumb, a soft cloth, whatever) will result in wear. All of this adds up to loss of detail and visible evidence of tampering. Take that into account before proceeding.

3) IF IT�S CIRCULATED, DON�T BOTHER Circulated coins that are dipped or otherwise cleaned almost always wind up looking very unnatural and very unattractive. If there is a distraction on your coin that has led you to want to �improve� it, dipping or cleaning is probably not your best option. A build up of verdigris (or gunk, junk, stuff, ugly, etc.) on part of your coin, for example, may not be effected at all by an attempt to dip or clean it away while the rest of the coin will be. Even if you succeed in removing part or all of the distraction there will usually be evidence remaining that shows it was once there. To put it simply, messing with ugly usually results in uglier. There are methods for treating coins with an excess of verdigris that are noninvasive that should be pursued instead.

There are many commercial products available to help you clean your coins. I�m going to stick with two for the purposes of this article because that�s all I�ve ever used. The two products I�m going to discuss are MS70 (basically concentrated soap) and eZest (a chemical dip). These are available for purchase from just about any coin supply dealer.

MS70 is a good product to start experimenting with because it�s relatively mild. The manufacturer claims it is safe for use on gold, silver, nickel, copper, bronze and brass. I�ve only used it on copper, silver and nickel so I can�t vouch for its performance otherwise. I have successfully used MS70 to remove haze from proof coins, tape marks from a couple of silver quarters and PVC residue from a Peace Dollar. The instructions on the bottle suggest applying it with a cotton swab and this is generally how I�ve used it. In the case of the tape marks I poured a little of the solution in a glass bowl, submerged the coins in it and allowed them to soak. I did this because using the cotton swab method would have required scrubbing, and friction is always a bad idea. After soaking for about five minutes I rinsed the coins in distilled water and the tape marks came off with no manual effort. 

The manufacturer of MS70 states that it�s only intended for use on mint state coins. This makes good sense to me as removing the normal grime of circulation from a VF coin would likely make it look terrible. I should also point out that the instructions on the bottle advise that �when using on copper do a few test coins to become familiar with how product works.� The only copper coins I�ve used it on were 1970s proof cents and I noticed no ill effects.

The other product that I occasionally use is called eZest and is a chemical dip. When I say I �occasionally� use it I�m talking about three times in the last four years. It is incredibly, ridiculously easy to destroy a coin using a chemical dip. Not just this particular brand of chemical dip, any brand of dip can do it. I don�t claim to understand the chemistry behind how these products work, but it simplifies to the idea that the top layer of metal on the coin is eaten away taking surface contaminants with it. Along with those pesky surface contaminants you will lose other annoying things like luster and details.

The manufacturer of eZest indicates that it is for use with copper, silver and gold. It cautions against use with other metals, especially platinum. I caution against dipping anything but silver, as silver is the only metal I have had even the slightest success with dipping.

The first coin I ever dipped was a 1962 proof Roosevelt dime. There was nothing particularly wrong with the coin aside from a bit of haze in the fields, but by gum I wanted to dip something! I still have the dime. I keep it in a binder with a bunch of other unfortunate coins I have accumulated (the Roosie is the only one whose misfortune I caused) to serve as examples of problem coins to me. The dime is now very dark and muddled in appearance because I dipped it too long (about ten seconds) and didn�t rinse it properly (tap water is no good for this purpose).

The only good experience I ever had with dipping came after I bought a Maria Theresia Taler from my local coin dealer. It had obviously been sitting in his shop for a few decades and was encrusted with the ugliest toning I have ever seen. The toning turned out to be about thirty years worth of cigarette smoke on closer inspection. I decided that since the coin was so ugly and so cheap (I paid $8 for it) I�d take a crack at dipping it. This time I decided to err on the side of caution. I dipped the coin for one second (the manufacturer recommends five) and immediately rinsed it in distilled water. The result was a blast white and highly lustrous $8 coin.

From my limited experiments with cleaning coins I have come to believe two things. The first is that a judicious dip of a silver mint state coin can occasionally have decent results. The second is that 99.9% of coins should not be cleaned - especially by me.

For the value of the experience you can gain I recommend that everyone do the following �experiment.� Get yourself a heavily circulated copper cent, a circulated silver coin (a beat up Franklin half will work nicely because they�re generally cheap) and the cheapest mint state silver coin you can find. First apply MS70 to the mint state coin following the directions on the bottle. After rinsing and drying (press between a folded cloth - do not rub or pat) note the effects. Now dip the mint state coin following the instructions on the dip you chose. After rinsing and drying note the effects (you should be able to notice some loss of luster even after only one dip if you look closely). Proceed to dip your circulated silver and copper coins and note the horrible effects.

Now that you�ve seen first hand what cleaning a coin can do you may have a better idea of what should and shouldn�t be cleaned. A side benefit of an experiment like this is that you may have an easier time identifying coins that have been fooled with. There are many techniques I didn�t touch on here (because I will only write from experience), but there are many knowledgeable members of this forum that will likely add to this post. So keep reading and when in doubt DON�T CLEAN IT!