Does Cleaning Coins Decrease Their Value?

When it comes to cleaning a coin, the general rule of thumb is simple: don’t clean your coins.

Cleaning coins is not only generally harmful to their value, but it can also irreparably damage their surfaces—rendering many pieces numismatically uncollectible.

Many people want to know if cleaning coins reduces their value, and the answer to this isn’t as complicated as some may believe—or perhaps may even hope.

We’re going to address some of the common questions that people have about cleaning coins and explain why this causes coins to lose their value.

Why Cleaned Coins Lose Their Value

This is a great question… There are several reasons why cleaning coins will make them lose their value. In the most basic sense, most collectors simply don’t want their coins cleaned. They generally desire originality—they want their coins to appear unadulterated.

Cleaning a coin permanently damages its surfaces by removing the outer layer of patina or toning. This patina may, in the eyes of some, make it appear “tarnished” or “dirty” (as many amateurs would say).

And how is this patina removed? Usually by scraping away a thin outer layer of metal on the coin.

The removal of this metal will often result in the appearance of countless tiny scratches or hairlines across the surface of the coin, which in the “best” of cases is only viewable under 3X to 5X magnification. In the worst situations, these striations are hideous and clearly visible on the coin even to the unaided eye.

photo of a coin graded 'Details' by NGC

This coin graded by NGC shows the "Details" grade given to improperly cleaned coins. Image via Pinterest

A large sector of the collecting market is turned off by such cleanings. As a result, it reduces a cleaned coin's numismatic premium because most of its potential buyers are no longer interested. Remember, most of a coin’s value is its numismatic value—a combination of factors that include rarity, grade, and eye appeal, and usually comprise the largest share of a coin’s overall value.

Additionally, if a cleaned coin is authenticated by one of the leading third-party grading services, such as NGC or PCGS, the coin will receive a "Details" grade. This indicates that the coin is no longer considered to have original surfaces. Coins with "Details" grades have a significantly lower value in the collecting marketplace.

However, even bullion coins can see a loss in value through cleaning. Bear in mind that most bullion coins don’t trade strictly along the pricing lines of silver or gold premiums. They typically also enjoy a little boost in value above that thanks to their numismatic value. This is the case even with American Eagle coinage, which typically trades at a premium above its spot price.

Consider, too, that especially harsh, abrasive cleanings can serve to remove enough metal from a bullion coin that it removes a measurable amount of valuable surface metal. This, of course, physically lowers the coin’s value.

How to Clean Coins Without Decreasing Their Value: Is It Possible?

Certainly, many people try to achieve what they may think is the best of both worlds by hoping to make their coins look new without harming their value. The only ways to “clean” a coin without impinging its value is to use non-abrasive methods that don’t alter the patination or toning on the coin.

So, how do you clean a coin without lowering its value? You do so by running it under a slow stream of tepid water and then patting (not rubbing) it dry with a soft cloth.

Another method that some might employ when trying to remove old adhesive residue or ink is to bathe the coin in 100% pure acetone. This is done in a well-ventilated setting for a few moments, then they rinse the acetone from the coin with clean, tepid water before patting it dry.

Either of the above methods will work to remove surface debris and residue without tampering with the coin’s color or toning.

However, neither method will satisfy the individual who is trying to make their chocolate-brown Lincoln Wheat cent look bright and orange as if it were minted yesterday. There is simply no way to achieve such a result on an old, circulated Lincoln cent, no matter the abrasive or chemical brew.

If such results were truly possible, the old, worn coin still wouldn’t look natural. Most collectors wouldn’t touch such an altered piece with a ten-foot pole, let alone pay for the chance to do so.

photo showing two No Grade coins in PCGS holders

Examples of "No Grade" coins. Image: PCGS

There is an ongoing debate in numismatic circles about "properly" cleaned and improperly cleaned coins. Some believe the proper way involves using store-bought formulas. Many such products are now marketed to collectors as cleaners, with names like "MS-70" and "Nic-A-Lene."

Countless coin collectors have also discovered their own DIY methods for cleaning coins at home. Whether "proper" or "improper," keep in mind that no cleaning method for coins is promoted or endorsed by any numismatic organization.

Should You Clean Coins Before Selling Them?

Here’s the thing about cleaning coins before selling them: Cleaning coins is most often done by amateurs who really have little knowledge about numismatics. They often think cleaning coins will enhance their value, or mistakenly believe that it’s a market preference to have all coins be bright and shiny.

(But, as we see throughout this article, cleaning only damages their numismatic value—and often by 20% to 50% or even more in worst-case scenarios.)

This philosophy isn’t unique to numismatics. If we look throughout the world of antiques, the same school of thought applies in almost all cases. There are relatively few areas in which cleaning something collectible will preserve or even enhance its value.

Interestingly, the realm of classic cars is one in which cleaning and polishing maintains collector value. But, even then, you should never use harsh, abrasive cleaning agents to clean a collectible car. Sound familiar?

One of the few times when it is numismatically acceptable to clean a coin before selling it is in the case of removing crud and oxidation from ancient coins that have been buried for eons. Cleaning is often the only method for identifying such pieces, and thus it is sometimes necessary to clean them before they are offered for sale. Even then, extreme caution should be used.

Many online forums that explain how to clean coins pitch abrasives or caustic chemicals that aim to completely remove patination from coins. These methods may satisfy the impulses of those who want to believe they are removing 100 years of dirt from an old coin.

But, what they are really doing in the process is completely removing the coin’s natural skin and, in doing so, are irreparably damaging its appearance, collectability, and value.

a bucket filled with cleaning supplies

Cleaning supplies and chemicals are likely to reduce the value of your old coins.

Should You Hire a Professional to Clean Coins?

If you have a coin that you feel needs help, the better option is always to consult a professional on the matter.

The major grading services offer restoration and conservation services. For a fee, these services can evaluate your coin and determine if a professional restoration can be performed on your coin to help improve its appearance without damaging its surfaces or overall value.

None of the services guarantees results, nor can they necessarily “fix” all things that some collectors may perceive as “problems.” But such professional services have been successful in making some coins that have ugly toning issues, surface residues, or other numismatic problems market acceptable.

Moreover, using the restoration service from PCGS or the conservation service from NGC are often the only way to avoid the aforementioned "Details" or "Improperly Cleaned" grade designations.

FAQs About Coin Cleaning

Does it always hurt the value of old coins to clean them?

It depends on who you ask. The adage "beauty is in the eye of the beholder" might apply here. If a collector just wants a shiny-looking coin, then perhaps cleaning won't negatively impact an old coin's value. However, for most coin collectors, any coin with altered surfaces is worth far less than normal.

How do you clean without hurting the value or damaging the coins?

There is no surefire way to avoid reducing a coin's value if you choose to clean it. As we pointed out earlier, it's a risky decision. But the best advice we can give is to use the least abrasive cleaning methods available, especially those that do not use harsh chemicals.

So are dirty coins worth more?

Not necessarily. Remember that there are authentic old coins that were simply well-preserved, and were never dirty. Nonetheless, coins that are toned or appear "dirty" are at least more likely to be genuine and therefore collectible. Moreover, an unaltered coin won't receive the dreaded "Details" or "Improperly Cleaned" designations when they are submitted for authentication and grading.

Can you boil old coins to clean them?

Boiling your coins for any reason is not recommended. Depending on the metal composition of a particular coin, the boiling process may result in discoloration or other damage to the coin.

How do professionals clean coins?

Both NGC and PCGS offer professional services that will, as best as is possible, improve the appearance of a coin. Positive results are not guaranteed, but it is a much better option than attempting to clean a coin yourself. The processes and methods used by these third-party grading companies are proprietary. Think of these services like an archaeologist lightly brushing the dust from an old artifact. It is intended to bring out the original details of the object rather than "clean" it.

Read more about the hobby of coin collecting from the experts at Gainesville Coins:

Collectors Hub: Resources for Understanding the Hobby of Collecting Coins

What Is a Brilliant Uncirculated Coin (BU Coin)? Beginner's Guide

What Is a Proof Coin? Overview and Collecting Guide

What Is a Gem Coin? Understanding Quality, Rarity, and Value

What Is an Uncirculated Coin? Guide to Condition and Value

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