Why you shouldn't clean old coins

Are you looking at your rare coins and asking yourself

Should I Clean My Old Coins?

It may be tempting to look up how to clean coins, grab that old 1888 Morgan silver dollar and try to give it a good polish, clean the years off of it, and really see it shine.

Dont.

Seriously, don’t.

Cleaning a rare coin, or really any coin can severely damage it, adding small scratches, or even ruining the finish of the coin.  Try to resist that instinct to make it “shiny and new” as much as possible.

In addition to potentially ruining the finish of your coin, you'll be ruining your opportunity to sell that coin.  Collectors will actually purchase a coin for the wear on it.  It tells a story, it adds something interesting to your coins, and adds to the overall appeal of the coin itself.  Meaning cleaning your coins will actually DEVALUE them.  Now your coin that was worth $5000 is now worth less than what you paid for it. Dang it!

Patina is highly desirable

Patina (The natural layers of toning a coin acquires over the years) is desired and appreciated on a coin.  Numismatists will outright decline on purchasing an old coin that’s been obviously cleaned. 

Think of it like a nice aged whisky, or wine.  It gets better as the years go on, adding depth and complexity to the flavor.  It’s much the same with coins (minus the flavor part of course, we do not recommend tasting your coins!)

Abrasive cleaners like baking soda, or acidic cleaners will actually remove bits of the metal every time they’re cleaned.  This can also result in pitting on the surface of the coin.

Using an abrasive cleaner on coins will activate the oxidation process, resulting in the coin darkening over a much shorter period of time than it normally would.  Essentially going back to or even worse than it was before it was cleaned.

Patina and toning is a natural development on a coin.  Different metals will develop different colors of patina, for instance silver will develop a light gray to deep brownish gray with dark recesses.  Gold is the least reactive, with gold you might see some warmer soft yellow colors for the patina.

Another type of cleaning, referred to as “whizzing” is done with an abrasive wire brush, this will leave countless tiny hairline scratches all over the surface of a coin.  Not very desirable.

Look For the Cartwheel Effect

After cleaning a coin, the surface and shine will look unnatural.  There will be no metal flow lines, and the cartwheel effect (if you tilt your coin while rotating it you should see light reflected almost like a windmill around the coin) will also be gone.

If you cannot be convinced, and you must have your coins cleaned, entrust them only to a highly experienced, knowledgeable professional.  (But again, we don’t recommend cleaning your coins)

When buying  collectible coins, be prepared to look out for coins that have been cleaned.  Keep in mind what was discussed here, look for that cartwheel effect, and the metal flow lines.  The coin shouldn’t be unnaturally bright and clean.  If you don’t see the windmill-like light effect, the coin has either been circulated or cleaned.

Try To Always Buy Certified Coins

One way around this is to always purchase coins that have been certified by either PCGS, or NGC.

As always, happy hunting and we hope you learned how to (not) clean your coins!

If you have a story about a cleaned coin, share it here! We’d love to hear about your experiences in the coin collecting world.