Should You Clean Coins Or Not? (Hint: NO!)

old-corroded-pennies-coins-by-Lottery-Monkey.jpg People entering the hobby of coin collecting (and those who’ve found a coin that might be valuable) usually want to know how they can clean their coins.

Questions like “Which way is the best way to clean my old penny?” or “How do I brighten up my tarnished silver dollar?” normally lead to one, impassioned answer: “Don’t clean your coins!”

It seems logical to some people that a bright and shiny coin would be favored by coin collectors. While that may be true to a certain extent, what is also true is that coin collectors prefer coins that display normal, natural color.

If a coin is bright and shiny because it was well preserved or just came from the Mint, that is a good thing. However, if a coin is bright and shiny because it was just dipped in vinegar and baking soda or was scrubbed with an abrasive like toothpaste, then coin collectors will shy away.

Why? Again, most coin collectors prefer coins that possess natural color.

It is true that, in many hobbies, a “cleaned” or “restored” item usually fetches higher prices than unkempt versions.

Yes, it is often the case that a cleaned and newly restored 1957 Chevy may get a higher price than a junked version of the same car.

Many times, you will hear of old paintings and linens on “The Antiques Roadshow” that appraisers say would fetch a higher price if holes were repaired and grime was washed away.

However, in coin collecting, numismatists tend to take the “old, fine wine approach.” That means, they value and appreciate coins that show their age.

 

Experts Can Tell A Coin Has Been Cleaned

coin-cleaning-photo-by-chrstphre.pngA true coin collector would rather have a deep, chocolate brown-colored penny that is 100 years old than a penny of the same age that has been cleaned to look new.

What also happens when a coin is cleaned is that it usually displays an unnatural color.

Some examples:

  • Pennies that have been cleaned often take on an unnatural, orange color. Sometimes cleaned pennies will show streaks or blotches of color.
  • Silver coins sometimes take on uniform grey colors that are otherwise unnatural for silver coins.
  • Any coin that has been heavily cleaned will have an unnatural, uniform reflectivity that coins would not normally show.

 

Values For Cleaned Coins vs Uncleaned Coins

So you’re probably wondering… what are cleaned coins worth, compared to uncleaned coins?

Like many aspects of coin collecting, there is little science in valuing cleaned coins versus uncleaned coins. Many aspects of judging a cleaned coin’s value are based on eye appeal. That is, how “nice” does the coin look?

  • A coin that has been so abrasively cleaned that it now has scratches or hairlines and has lost its luster will rarely be worth anything more than half its original, uncleaned value.
  • A coin that has been only lightly cleaned (and is not scratched and doesn’t have much evidence of impaired luster) may be reduced in value by as little as 10% or as much as 30%.

However, there is no “rule” for such values. Pricing of cleaned coins is often done on a case-per-case standard. Percentages mentioned above are the more common price discounts I have seen over the years for cleaned coins being offered from dealers.

 

Is There A “Safe” Way To Clean A Coin?

There are relatively few occasions when it is considered recommendable to clean a coin.

Normally, coins that are encrusted in dirt can be safely cleaned with simple, clean water. It is usually okay for the coin to sit briefly in the water — so as to give the dirt time to gently dissolve. Pat, don’t rub, the coin dry with a soft towel.

Removing loose debris is acceptable in coin collecting.

The controversy about cleaning coins usually comes into play when a person is attempting to remove the natural color or patina that a coin has taken on.

For example, rubbing just about anything on a coin will leave scratches and fine lines on the surface of the coin. While to the novice eye, these lines may resemble the luster and shine seen on new coins, the lines actually represent irreparable damage to the coin.

Regarding pennies, all of those coin cleaning methods you’ve heard so much about – from vinegar to baking soda to erasers — actually strip away the natural toning (tarnish) that your pennies have taken years to develop. The deep browns seen on most older pennies are colors that most coin collectors actually desire. So when a penny with even, brown or chocolate colors comes your way, leave it alone!

 

What About Corroded Coins?

green-pennies-corroded-coins-by-Lottery-Monkey.jpg If your coin has suffered damage from polyvinyl chloride (PVC), the coin will usually have green residue on its surfaces.

The green residue is a sign that the metal in the coin has begun reacting to the plastic. This reaction is usually dangerous for the coin and progressively can get worse. In time, the coin can become irreparably damaged.

Professionals can safely handle the removal of most PVC damage. There are also ways you can remove PVC on your own. I do stress, however, that trying to remove PVC damage can be inherently dangerous for 2 reasons:

  1. You may further damage your coin while trying to clean the residue off; and
  2. The chemicals involved in removing PVC can be harmful to handle and can be flammable.

 

More About Cleaning Coins

Joshua McMorrow-Hernandez

My love for coins and numismatics began when I was 11 years old. I primarily collect and study U.S. coins produced during the 20th century. I've also been studying meteorology and watching weather patterns for years. I enjoy sharing little-known facts and fun stuff about coins, weather, travel, health, and living green with others.

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  • Jennifer

    Hi! I was given a bunch of old US-Philippines circulated coins and I cleaned them. So, now I have ruined these coins. what is the best way to restore it back to its old state? Time? Any input will help. Thank you!

    • Anonymous

      Hi Jennifer –

      We all learned the hard way — including me — about cleaning coins. Unfortunately, once a coin has been cleaned, it will always “be cleaned.”

      Time will help restore a patina that will help the coins look less harsh.

      If you’re looking to “do” something to the coins to make them appear less shiny and planning to keep the coins for yourself, you could impart some artificial toning. Place the coins in a paper envelope and leave them in direct sun (such as on an indoor window sill) to help restore some color to the coin (sulfur and heat are two methods of toning coins).

  • Dannybruiz

    Uhhmm…the only coins collectors are looking for are dates, where it was minted, what the silver amount, etc. They don’t care about average silver coins…All Silver coins are primarily sold for their silver content based on the silver market..so cleaning and polishing a silver coin makes no difference to the value. Again…Unless its a special coin..

  • daduvksh3851

    What’s wrong with soaking them in water and wiping them with a soft cloth? Many of the coins circulating have been thus treated?!

    • JoshuaTheFunTimesGuide

      It’s true that many coins have received worse treatment in circulation, but the credo in coin collecting is to leave coins as they have been found, for even the slightest rubbing can further wear a coin down or impart further damage.

  • Linda Widmer

    A customer sent me a coin to be wire wrapped that she had cleaned. The coin is an 1896 Morgan Dollar. It looks like the silver has rubbed off and left spots of copper showing. Is there any way to restore it to its rightful silver color? I do not know what the owner cleaned it with.

    • JoshuaTheFunTimesGuide

      Hmm, even though most U.S. silver coins have a little bit of copper in them, it shouldn’t really appear as you have described. Usually, coins that are 90% silver appear silvery all the way through. It may be that there was some type of environmental damage to the coin that would cause the spotting you describe. Plating the coin with silver might restore the silverish color that you desire.

  • Linda Widmer

    Thanks for the info Joshua. I contacted the customer and asked what she had cleaned the coin with and she said it was a “silver cleaner” and that she had scrubbed the coin vigorously. Anyway, she still wants it made into a pendant so all is not lost. Once again, thanks!

  • Carlos Valentin Jimenez

    hi i have alot of silver hidalgo coins from mexico but 3 look really bad should i clean them a bit

    • JoshuaTheFunTimesGuide

      Hi, Carlos -

      It depends on what you mean by “really bad,” but without seeing the coins I can with confidence say that it is probably better off leaving them in the “original” condition by not cleaning them than to try and improve their appearance by washing them in some way. If you would like to post pics here of your Mexican coins to this comment board so I can see them and render a specific opinion, please feel free to do so!

  • Mark Chaplin

    I have an expensive high grade Australian florin, it has a small dark ugly patch which looks like a scorch mark. Can I clean it safely?

    • JoshuaTheFunTimesGuide

      Hi, Mark -

      If it is a scorch mark, then the extreme heat would have quite possibly reworked the chemical structure of the penny anyway and caused discoloration below the surface of the coin. Therefore trying to remove the discoloration will mean having to remove the metal on the surface of the coin, damaging it. I would personally forego cleaning the coin altogether.