The Cardinal Sin Of Cleaning Coins And How To Remove Grime

I agree with your opinion.

One of the most asked questions on this forum is about How to clean coins . There is a right way and a wrong way to do so . If you want to clean your coins, you need to be experienced at it. If you don't know what your doing you can ruin a valuable coin . Read up on our coin cleaning forum and ask questions before attempting a major restoration job .

Over the years there have been so many suggested types of cleaning of coins. Olive oils, all kinds of soaps, mild acids, Tomato and Lemon Juices, toothpicks, place in freezers, WD-40, battery acid and on and on and on. I just don't know why people just can't leave coins alone. Yes a little dip in Acetone is OK but why keep on messing around.

Was that just acetone or acetone + verdi care?

The "harshness" of a chemical is entirely dependent on what chemical reactions you are expecting to occur. Acetone is a "harsh" solvent, in the sense that it will dissolve or depolymerize many kinds of plastic; it's also rather flammable. But it does not react with metals or metal oxides/salts at all. So it's great for removing plastic-like "grime" from coins without damaging the metal or the patina/oxidation layer.

The general advice "don't clean coins" is the default position for coin collectors, for two reasons.

1. Because things that everyone else out there calls "dirt" or "grime" are not necessarily things that a coin collector wants removed from the coin. Paint, glue, varnish, sticky-tape? Sure, remove them with extreme prejudice. Toning, tarnish, oxidation? Leave it there, don't you dare remove it. Yet to a non-coin-collector, it's all "dirt".

2. Because the correct cleaning of coins is actually rather hard to do properly, and very easy to do badly. Further, most kinds of cleaning don't have an "undo button" - you can't change your mind, decide you liked the way the coin looked before you tried to clean it and dis-clean the coin again. Coin cleaning is irreversible, and a botched cleaning job is irreversible too.

I've had "failures" in my coin cleaning experiments - treatments which either did nothing at all, or which made the coin look worse. Over a decade ago I tried various chemicals and compounds, up to and including ammonia, on an old corroded Australian copper token with a nasty case of active verdigris; you can see the results in this old thread, and judge for yourself whether the coin looks "better", "worse" or merely "different".

I've also had some successes too. Check out the results I obtained cleaning up a debased-silver Australian coin with severe corrosion, using a soak in 5% disodium EDTA solution for several days:

Before:


After:

Nice job Sap and Chute72. You saved coins that would have probably corroded away completely and aren't high value rarities.
thumbs up.

I have never cleaned a coin to where I felt the coin was ruined and most of the time the cleaning is because I can't read the date. I have a rag I keep handy to rub coins with that are tarnished and it is hard to read the date. So mostly the cleaning/polishing is an effort to read the date and especially the mint mark.