What Not Online Auctions

HomeIs It Ever OK to Clean Coins?

Is It Ever OK to Clean Coins?

By Peter Mosiondz, Jr. for CoinWeek …..
Some types of coin cleaning might very well improve a coin’s appearance, while most other methods may actually damage the coin’s surface, appearance and–most importantly–the value.

If I could offer just one piece of advice to you today, it would be this: Do not clean your coins under any circumstances.

That being said, many collectors will want to try cleaning their coins in a misguided effort to improve them. Sage advice sometimes falls on deaf ears. Many experts, who have been in the hobby numerous years, have tried and failed in most instances.

This, by no stretch of one’s imagination, will not be a how-to article on cleaning coins. Instead, we’ll discuss the methods of cleaning for those who will not heed our warning. All we ask is that you don’t come crying to us when a perfectly good coin has been ruined for all time. We have been in the hobby for nearly 60 years now (we started very, very young!) so our counsel is measured with a good deal of experience.

As we said, not all cleaning is bad or injurious in itself. What we’re saying is that certain methods should be entrusted only to a very experienced and knowledgeable professional. Stop to consider for a moment that you would not take it upon yourself to restore or improve a valuable painting. You would seek out an individual best equipped to handle the project, an expert. The same adage applies to our coin hobby.

Before going any further, we suggest to those who are going to attempt to clean despite our admonition to experiment first on coins of little or no premium above the face value, or denomination. Coins found in pocket change make good test subjects. Any slight bit of mishandling or mistreatment on a more expensive coin will adversely affect it both aesthetically and monetarily.

In basic terms, there are two types or methods of cleaning coins. They are identified as abrasive and non-abrasive.

Abrasive cleaning will always remove some part of the coin’s metal, regardless if you can see it or not. This is a cold fact. Abrasive cleaning is, without any doubt, the more harmful of the two methods and should never be considered.

What is abrasive cleaning? It is the process of using an acidic substance or a wire brush on the coin’s surface. The wire brush technique is often referred to as “whizzing”.

Abrasive cleaning also activates the oxidation process of a coin’s metal. The coin will more likely than not turn dark over a relatively short period of time.

No doubt you are familiar with the various coin “dips” on the market. They must sell like hotcakes because there are several brands available and they are continually advertised. But did you also know that most of them are acidic? No matter how alluring the label on the package reads, my advice is to steer clear of these products or exercise extreme caution if you insist on trying one or the other brands out there.

While it is certainly true that a quick dip of a fraction of a second may not cause too much obvious damage, it will still remove some metal, no matter how slight.

The resultant surface will have an “artificial” look. The original metal “flow lines” will be gone and you lose that wonderful “cartwheel” effect that makes an uncirculated coin so appealing.

coin_dippingThe coin’s flow lines originate in the minting process and give the coin its reflective properties. Dipping, even for a millisecond, will reduce or eliminate these flow lines. The coin will also lose its natural mint-made lustre. Dipping, no matter how slight, may very well cause “pitting” on the surface. Remember also that the longer the dip the more the potential damage. It can, and usually does, turn an OK coin into a dog. The dipping does not last forever as we shall soon see.

Have you ever seen a blazing “white” U.S. Morgan silver dollar without any evidence of even a slight bit of toning? These coins are well over 100 years old and, except for the hoards released by the U.S. Treasury about 50 years ago, it is virtually impossible for any silver coin that old to be as bright and shiny as the day it fell off the coining press. The answer is a quick dip. Toning is a natural phenomenon to any silver item, including coins. Toning is as much a part of the coin’s aging process as wrinkles are to you and me as we advance in age. No matter how careful grandma was with her silver place setting and no matter how carefully it might have been wrapped, toning occurs and the silver cleaner comes out.

As to the dipping not lasting forever, I personally have witnessed many coins that turned dark or had black specks and spots in a relatively short period of time. One incident in particular is the sad story of a group of commemorative coins I dispatched to a major grading service in the states. The coins were duly received by my client and he was well pleased with the assigned grades, even remarking at the time that some of the coins actually “looked better”. He had bought them unencapsulated from a trustworthy source, or so he believed.

My friend called me less than a year later in an almost panic-stricken voice. I went right over to his apartment. Five of the coins turned either completely dark or had numerous black specks here and there. I sent them off to the company that had encapsulated them with a note describing the circumstances. Two weeks later all five coins were returned in new holders and were completely “white” again, albeit without the flow lines or cartwheel effect. The return shipment also included a letter of apology, which was nice but did not address the problem in the first place. You guessed it! They dipped the coins. This in spite of the fact that they did then, as now, state that they do not dip coins and do not grade dipped coins. Caveat emptor.

The point to remember is that a dipped coin will either return to its previous non-dipped state or worsen over time.

As to the non-abrasive cleaning method, a professionally performed non-abrasive cleaning will not, in most instances, subject a coin to lose its metal flow lines or aesthetic qualities. If carefully and professionally accomplished it should not cause any pitting on the coin’s surface nor should it cause the artificial look so prevalent with abrasive cleanings.

In the past, I have briefly submerged a coin in a warm distilled water bath. The results were, for the most part, satisfying. I first practiced on several coins from my ordinary change. A friend of mine has reported success using a bath of denatured alcohol. I haven’t tried it myself so can not comment on its merits or lack thereof.

There are certainly other non-abrasive methods that a professional can point out to you. Consult first and make certain that this is what you want to do. You will not receive any guarantee that the process will work with any degree of satisfaction on your behalf.

Some pointers are in order on the buying side so as to help you avoid cleaned coins.

Take precautions based on what we have already discussed. When contemplating the purchase of a brilliant uncirculated (or Mint State) coin, look for the metal flow lines that emit that wonderful reflective glow that we collectors are so fond of. When slowly rotating the coin as it is tilted to and fro, you should see that “cartwheel” effect that we mentioned earlier. In other words, you should notice the effect of a wheel emitting rays of natural reflection. If you do not see this cartwheel effect, my guess is that the coin has been dipped or is not uncirculated.

Take a close look at toned coins as well, especially if they are not encapsulated by a third-party grading service. Sometimes a devious soul will produce an area of artificial toning on a coin so as to hide a previous cleaning job or some defect such as a gouge.

As always it is best to deal with qualified and competent professional numismatists when buying coins or, heaven forbid, considering cleaning.

If all of our admonitions have fallen on deaf ears, we suggest the following if you must dip:

  1. Follow the instructions on the label
  2. Always work in a well-ventilated area
  3. Always wear gloves
  4. Wash your hands with antibacterial soap in warm to hot water after each session
  5. Experiment first with coins of little or no value
  6. Read this article again and maybe you’ll be convinced not to dip

Until next time, stay well and enjoy your hobby.

Related Articles


  1. People often describe the extreme forms of abrasive cleaning only, like a wire brush, etc. But I think more people use less extreme albeit abrasive cleaning that is not market acceptable. For instance, a while ago I used to use q-tips and acetone to clean my coins. Cotton and acetone are not abrasive, right? Especially if didn’t rub the q-tips hard. But with mint state coins and especially proof, any rub with a q-tip and acetone is not a good idea. It’s abrasive because it’ll show up. I’ve now learned to roll the q-tip with acetone, instead of swipe it across coins. Lastly, I wouldn’t advocate ever the use of anti-bacterial soap. Regular soap and water is enough to clean hands. Anti-bacterial soaps can lead to resistant bacteria growth and harm the environment

  2. I found a 1943 circulated half dollar in a roll recently.
    It is very dirty with splotches of something on it.
    Is dish soap and a rag ok to try to remove the gunk ?

  3. I found a 1883 as well as 1783 coin but its kinda dirty with grim on it.
    Other than that, the cartwheel etc are quite well preserved…only thing its surface is not pure copper / whitish metal look but slightly dark with unknown grim on it that makes it look dark.
    Issit ok if its left to clean so as to see better the details?

  4. You heard the man. DO NOT CLEAN YOUR COINS!! What part didn’t you understand?? So why are you asking questions on cleaning methods?

  5. Hello,, a few years back I acquired about 60 pre war nickels,, 40% silver as we all know,, and they looked like crap,,, so I decided to give them a hot soapie bath , they came out a little better, but still looked shity,, so a few days later I gave them a quick acetone Deluded wash,, and the they looked great. ( kinda ),, so I figured I would leave them over night,,, now there all black,, bummer ,, don’t clean your coins.

  6. Banks clean coins. I.use. tablespoon dawn quart dist.water q tip or soft toothbrush protect with mineral oil . You guys keep your dirty coins .I wont even look.

  7. I was just reading an article on the damage PVC holders can cause. My dad had a Harco holder of Washington quarters. At first glance I see no obvious pvc damage but see other examples of the ‘green slime’ that happens. A community board then goes on to recommend a 100% pure acetone bath to resolve the problem. Several board members discuss their success with it, soaking the coins for days, following a fresh 100% acetone flush, then air dry. Is this a bonafide and safe cleaning method?

  8. I just put mine in the glass dishwasher rack to get oil and normal grime off from circulation ? Does removing normal dirt matter ?


Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Bullion Sharks Silver

L and C COIN Shop Now

NGCX Holders and Grading