How to Clean Coins

A person examining a collectible coin collection.

I’m not trying to be a bragger, but I’ve gotta tell you, I have a pretty impressive collection of old coins. It’s all thanks to my grandpa who’s now starting to push 90-years-old. He’s been an avid coin collector since he was a young man. About ten years ago, he decided (luckily for me) to get my brothers and myself in on the fun. He gave us all a nice starter collection of old American coins dating anywhere from about 1880 to 1930. I’ve got some nice old silver dollars, fifty cent pieces, mercury dimes, old pennies, nickels, etc. If I weren’t such a lazy S.O.B., I’d go pull them out of storage and list a few off for you. Alas, a zebra can’t change his stripes.

A couple years ago, after moving to the Twin Cities, I got curious not only about the value of my old coins but also about what I could do to increase their value. So, I gathered a few of them together and took them to the dude at the coin shop. I’m willing to bet you already know what he told me. Yup. Don’t touch ’em. Turns out, cleaning coins can severely diminish the value of your coins, sometimes by up to 90%. Not only is it really easy to scratch the face off your coin if you’re not careful, but, by cleaning, you risk removing the natural oxidation/patina. Which, in the coin biz, is known as “toning.” Turns out, the toning is something that coin collectors and dealers value greatly. However, it is common for collectors to be far less picky than dealers. If the coin has been cleaned properly, a collector may not give a crap. For that matter, you might not give a crap either. What’s to say you’re even looking to sell? If you’re not, then screw the monetary value, as that coin is priceless to you. So what if you want it to look a little nicer? There’s nothing wrong with shiny. Maybe you just want to use it for jewelry or are just getting a kid going on coin collecting. No matter what your reason, I’m sure you’d rather not do any damage through improper coin cleaning. That’s why I wrote this article. This is an easy, natural, and low-impact method for coin cleaning.

How to Clean a Coin

  1. coin collection in form of dollar signDetermine the value (just in case). For some people, this is an important first step. If you’re concerned about the value of your coin, it’s just best to be sure. Before you start messing with your coin, wash your hands so you don’t transfer any dirt, oil, prints, or whatever to the coin. The best way to do this is to take it to a dealer and see what they have to say. Otherwise, get yourself a coin pricing guide or try to look it up online.
  2. coins under running waterRun some water over the coin. The first step towards a clean coin is to simply run some hot water over it. First, make absolutely certain that there is no way that your old coin could end up going down the drain or the garbage disposal. Next, get the water hot by turning it up as high as it will go. Third, holding the coin by the edge between your thumb and forefinger, hold it under the stream. Keep the coin there for a couple minutes; flip it over, and do it again.
  3. soaking coin in dish detergentGive the coin a good soak. The next step in the quest to clean coins is just as easy as the previous step. Soak it. Mix together 1 tablespoon of mild dish detergent (e.g., Seventh Generation or Method) with two cups of hot distilled water. Try not to make suds. They take the soap out of solution. You may need to soak the coin from anywhere between 2 hours and 2 weeks. Check it after a short short period of time and go from there. Do not soak coins made from different metals together, and make sure you soak them in a plastic or glass container.
  4. brushing coinComplete the coin cleaning process. Once the coin is done soaking, run it under hot water again just like before. This may be enough to dislodge any remaining bits of yuck. If not, grab the softest tooth brush possible, wet it with hot water to soften the bristles further, and brush the coin very gently. Take great care to not rub in any bits of dirt, as they can scratch the surface. If you don’t trust the toothbrush method, and you do it gently, you can use your fingertips. If there’s still some stubborn spots, use a toothpick to carefully dislodge them.
  5. final rinse of coinGive it a final rinse and let it dry. Once you’ve done what you can to clean old coins, it’ll be time for one final rinse. For this, it’s best if you can use distilled water. Distilled water has no minerals and will allow your coins to air dry without worry of water spots. Pour some distilled water in a clean glass or plastic dish, hold the coin by the edges, dip it in, and shake it around underwater. Allow coins to air dry on a soft cotton towel. If you don’t have distilled water, run them under the tap for a few seconds on each side, set them on a soft cotton towel, and pat dry. Never rub.
  6. coin storage envelopesIf you’re cleaning coins for collecting, store them properly. This is really easy, fairly cheap, and there are many ways to do it. The idea here is to keep coins from rubbing up against each other and getting scratched. Go to any coin store and get some acid-free envelopes. They’re cheap, easy, and you can label them. At the same coin store, you will also be able to find flips, little plastic baggies, and coin albums. Flips are little plastic envelope lookin’ things. The nice thing about these is that you can see your coin. The baggies are fine too. Just make sure the plastic contains no PVC, as this can permanently damage your coin. If you live in a humid area, put some silica gel in the container that holds your old coins.

Other Ways to Clean Coins

Don’t like the above method on how to clean a coin? That’s OK. There are lots more. Just keep in mind that the coin cleaning methods below are not as gentle as the one above and are not intended for cleaning coins that are valuable or collectible. These are simply a few ways to make a coin you like a little prettier.

  • Ketchup. This is very simple. Fill a plastic bowl with about a quarter cup of ketchup and sink your coin down into it. Wait for about ten minutes before retrieving it, and give it a good rinse under warm water. The acid from the tomatoes and vinegar in the ketchup do a nice job of removing oxidation. Works great for cleaning pennies.
  • Lemon. A quick soak in lemon juice is a good way to clean pennies or silver coins. Place your coin in a glass or plastic bowl and cover them with a small layer of juice. Let it soak for a few minutes and check the progress. If you think it needs more time, give it more time. Otherwise, remove the coin, rinse it off with distilled water, and let it air dry.
  • Vinegar & Salt. I’m pretty sure there’s nothing that can’t be solved with vinegar. Mix two tablespoons of table salt with one cup of white vinegar, and toss your coins in. Make sure not to mix metals. Let the coins soak for a few hours or even overnight. Take ’em out, rinse ’em off with distilled water, and let ’em dry. You can get it pretty much anywhere, or order the vinegar straight from Amazon.
  • Baking soda and water. Get a box of plain ol’ baking soda and pour a little of it into your hand. Grab the coin to be cleaned, dip it in water, and roll it around in the baking soda. Next, use your fingers to rub the baking soda into the coin. Rinse it off and repeat, if desired. Keep in mind that this method is pretty harsh.
  • Rubbing (isopropyl) alcohol. This is just another substance you can soak your coins in. Keep different metals separate, plop them in a plastic or glass container with some alcohol, and let them soak. Again, check it after a couple hours; if you want better results, let it soak longer.
  • Olive oil. This is one of the most gentle ways to clean coins. Simply give ’em a good soak in olive. Use that same glass or plastic dish I keep blabbing about. Not only is this method gentle, it’s also extra slow. Don’t be afraid to let the coin soak anywhere from a few days to a few months.

Resources to Check Before Cleaning Cloins

coins red bookRed Book. This is one of the best known price guides for United States Coins. Before cleaning coins, pick up one of these and figure out what you’re dealing with. This is a very straightforward and easy-to-use guide that will tell you exactly what to look for when pricing your coins.

NGC logoNumismatic Guaranty Corporation. The NGC is a coin grading service worth looking into. The grading of a coin is the process of determining the condition (grade) of a coin. This is a great organization to submit your coins to to find their worth.

PCGS logoProfessional Coin Grading Service. The PCGS is another great resource for coin grading. You can submit your coins, learn what you want to know, and carry on with life. They also have a very nice online price guide.

About the Author

Eric D. Ronning

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