Expert Tips for Cleaning Copper Coins (Without Damaging Them)

Whether you have a whole collection of copper coins or you just found a cool-looking penny on the street, you might be looking for ways to get them clean and shiny. Just know that cleaning coins significantly reduces their value—in other words, if you’re interested in selling your copper coins, don’t clean them! In this article, we spoke to numismatics expert Max Hockley for his advice on when it’s wise to clean them and how to do it safely. If your copper coins aren’t valuable or you’re not looking to collect and sell them, we’ll also share several easy ways to get them sparkling clean (without damaging them).

Note: If you suspect your coins have any possible value, do not clean them. Cleaning them lowers their value and can damage them. Instead, take them to a coin expert to get them appraised and follow their cleaning recommendations.

Best Ways to Clean Copper Coins

Numismatics expert Max Hockley says to get your coin appraised by a coin expert before cleaning it. If the coin is valuable and you want to sell it, do not clean it, as this significantly reduces its value. If it isn’t worth much or its value is irrelevant to you, Hockley suggests rinsing it with water and dish soap.

Section 1 of 6:

Should you clean your copper coins?

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Get your copper coins appraised first to determine their value. Before you pick up any kind of cleaning tools or solutions, Hockley says to take your coins to a numismatist or other coin expert at a coin store.^{[1]
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Max Hockley
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Expert Interview} They’ll take a look at your coins to determine their history and condition, appraise them, and share how valuable they are. Depending on their value, the coin expert may advise you not to clean the coins or share their recommendations on how to safely clean them.
- While you might want to clean your coins right this second, Hockley notes that the coins have likely been dirty for a long time. So, waiting a few extra days to get them checked out by a coin expert isn’t really a big deal in the grand scheme of things.^{[2]
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- There are a lot of potentially valuable copper coins out there, like the Lincoln wheat penny, the 1944 wheat penny, and double die pennies.
Meet the wikiHow Expert

Max Hockley is a numismatics and precious metals expert who shares his insight with his 137,000 subscribers on YouTube.
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Do not clean valuable copper coins if you want to collect or sell them. Cleaning a coin can take its value down by 90%, says Hockley, as “the value of a coin is very dependent on its condition.” While clean and shiny coins might look nice, he explains that coin collectors base a coin’s value on the mint date, minting factory, and the mint luster, “which is the layer of shine that basically comes from the coin being struck at the mint with the different dies and the different polishes.” This is what “gives it depth and character, and is what the collector is looking for,” Hockley notes.^{[3]
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- “When you clean [coins], you strip away all that…mint luster” and “environmental toning and patina that's layered on top of those coins over many, many years,” warns Hockley. “From a collector's perspective, it looks completely uniform…and there's no character left to it whatsoever,” he explains.^{[4]
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- Hockley adds that coins are graded using the Sheldon Grading Scale, which gives a coin a score from 1 to 70. He says the second you clean a coin, it no longer gets graded. Instead, “it gets encapsulated in a label that just says ‘cleaned’ and it's considered damaged, effectively,” Hockley explains.^{[5]
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- As an example, Hockley says a coin that looks dirty and cruddy could get a grade of 62 and be valued at $1,500. However, if you cleaned it, its value could plummet to $60.^{[6]
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Clean coins that aren’t valuable, or if you don’t care about their value. Deciding whether to clean your copper coins is ultimately a personal choice. If the coin isn’t worth much, you aren’t interested in collecting and selling coins, or you simply want it to look nice and shiny, you may decide to clean it. For example, Hockley says you might decide to clean a coin that’s worth $40 because cleaning it will only take it down to $20. Or, he says that you might want to make a coin more visually appealing because you plan to wear it as jewelry or frame it.^{[7]
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- Additionally, Hockley notes that collectors generally believe it’s okay to clean coins that you find in the ground that are so dirty or corroded, you can’t even tell what they are. He just advises using gentle cleaning methods to avoid damaging it.^{[8]
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- According to Hockley, the reality is that “you can't identify a coin with mud caked on it” or “sell a coin that has mud caked on it.”^{[9]
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  Expert Interview} So, lightly cleaning it is usually necessary.

Section 2 of 6:

Expert Advice for Cleaning Coins

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Rinse the coin with water, without rubbing it. “The best way to clean coins once you've determined that they're not valuable and once you've determined that…you can't see what it is without cleaning it,” says Hockley, “is [to] go from least abrasive to most abrasive.” For the least abrasive option, he suggests simply holding the coin under running water or dipping it in a bucket of water to remove any dirt, mud, sand, or other loose debris.^{[10]
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- Do not rub the coin with your fingers or brush it with a tool as you rinse it off, warns Hockley. You might rub the dirt or debris into the coin, which can scratch it.^{[11]
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Lightly rub the coin with water, and add a bit of dish soap (optional). “Once you're able to see [the coin] a little better under the water, then you can lightly start rubbing off any caked-on dirt,” says Hockley. Just be super careful not to scratch the coin. If you want to clean the coin a bit more, Hockley suggests adding a little bit of mild detergent to your fingers, such as dish soap, and rubbing the coin under warm, running water.^{[12]
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- Reminder: Even if you gently clean your coin off, Hockley says, “It's still going to be considered a cleaned coin and it's still going to sell less than if it were, you know, in mint state condition or even any gradable condition.”^{[13]
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Use a slightly more abrasive method if you want to get your coin completely clean, says Hockley. He suggests using a toothbrush and a little bit of dish soap or baking soda to scrub the coin. Just use very light motions to clean it off.^{[14]
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Use a more abrasive method if you want the coin completely clean. “If you've already determined that the coin is not valuable or the amount that it will be reduced by cleaning it is irrelevant to you, then you can clean it any way you want,” explains Hockley.^{[15]
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- There are several simple ways to clean copper coins, including with vinegar, ketchup, vegetable oil, and baking soda. We explain how to use each method in the sections below!

Section 3 of 6:

Removing Dark Spots with Vinegar

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Pour 0.25 c (59 mL) of white vinegar into a small bowl. The coins need to be submerged in the vinegar, so make sure the vinegar doesn’t have too much space to spread out. If you plan on cleaning off a lot of coins at once, use a bigger bowl and add more vinegar as needed.^{[16]
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- Some other options to use in place of vinegar include orange or lemon juice. Like vinegar, citrus juice is acidic and wears off copper oxide on coins.
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Mix 1 teaspoon (5.69 g) of salt with the vinegar. Stir the salt until it dissolves in the vinegar. The salt helps lift black spots off old copper coins. Use more salt as needed to make the solution stronger for particularly worn coins.^{[17]
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- Keep in mind that adding more salt to the solution makes it stronger. Mix in extra salt if you wish, but keep a close eye on the coins to avoid damaging them.
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Soak the coins in the solution for about 5 minutes. Drop the coins into the bowl, spreading them out so they are all submerged. Try to arrange them in a single layer so the solution reaches both sides of each coin.^{[18]
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- For a more gradual treatment, leave the coins out of the bowl. Instead, dip a soft-bristled toothbrush into the vinegar solution and scrub the coins with it.
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Rinse the coins immediately with warm water. Clean the salt and vinegar off every coin as soon as possible. If you leave the coin alone, the acids continue wearing away the copper. Eventually, exposure to salt causes green spots to form on copper coins.^{[19]
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- Hold the coins under running water to ensure all of the cleaning solution rinses off. Don’t leave them in a bowl of water, since the vinegar solution and copper oxide will end up in the bowl and on other coins.
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Dab the coins with a microfiber cloth and let them air dry. Set a cloth down on a flat countertop, then place the coins on top of it. Arrange the coins in a single layer so they all have a chance to dry without the risk of picking up leftover vinegar or oxide. After drying the coins off as much as possible, leave them exposed to open air for about 5 minutes to eliminate any remaining moisture.
- Soak the coins in more salt and vinegar if they still look dirty. It may take a few treatments, so work gradually and wash the coins off each time to avoid damaging them.
- Vinegar solutions are effective for removing dark spots on coins, but they also tend to make coins look a little dull. Shine the coins to make them look better.

Section 4 of 6:

Stripping Patinas with Ketchup

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Cover the coins with ketchup or another acid. Pour some ketchup into a small bowl, enough to cover the coins. Submerge the coins in a single layer in the ketchup. Make sure both sides of each coin are evenly coated. Tomato sauce is acidic, and ketchup is made with salt and vinegar, so it’s extra effective at stripping blemishes off old coins.^{[20]
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- Hot sauce and brown colas are some other household substances that work well on copper coins.^{[21]
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- If you don’t have ketchup or another acid, try using a metal polish from a general store. It works similarly to ketchup.
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Scrub the coins with a soft-bristle toothbrush. Press the bristles very gently against the coins to avoid scratching them. Use the brush to work the ketchup into the dirtiest spots on each coin, such as around the lettering and outer edge.
- If you don’t have a brush available, leave the coins submerged in the ketchup for at least 5 minutes. Check back on them every few minutes, especially if you use a highly acidic substance like cola, to avoid damaging them.
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Rinse the coins off under warm water. Clean off all of the ketchup so it doesn’t continue to abrade the coins. Most of the patina, or the green or brown film on older coins, will come off as well, leaving you with a pink, clean piece of copper.^{[22]
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- Newer coins, such as relatively shiny pennies, tend to dull a little when washed in acid.

Section 5 of 6:

Washing Coins with Vegetable Oil

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Clear dirt off the coins with a toothpick. Scrape away the dirt around the engraved parts of each coin, such as letters or images. Also, remove as much dirt as possible around the edges of each coin. You do not need to remove all of the dirt on the coins, only enough to make the engraved portions stand out.^{[23]
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- Clearing away the dirt now makes the coin look clearer once you add the oil to it.
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Rub a small amount of vegetable oil onto each coin. Work the oil in with your fingers. Scrub away and add more oil as needed to make the coin appear shiny and refreshed.^{[24]
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- Use sparing amounts of oil to avoid damaging the coins. Remember, you can always try cleaning a coin again, but you can’t reverse mistakes.
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Rinse the coins under a trickle of hot water. Let the water drip from the sink faucet to avoid soaking the coins. As you wash the coins, continue rubbing them with your thumb to reach all of the oil. Any debris will come off, leaving you with pristine coins.^{[25]
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- Repeat the treatment with more oil as needed.
- For a stronger treatment, let the coins soak in oil for about a day, then scrub them with a soft toothbrush.
Lay the coins on the cloth to wick away excess moisture. Tap them with part of the cloth to dry them further. Before storing the coins, leave them out and exposed to the open air for about 5 minutes.^{[26]
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Section 6 of 6:

Shining Dulled Coins with Baking Soda

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Combine baking soda and water into a paste. Set out a clean bowl, then fill it with about 1 tablespoon (14.4 g) of baking soda. Gradually pour in about 1 teaspoon (5 mL) of lukewarm water, stirring it the entire time. Stop adding water as soon as the mixture has the consistency of toothpaste.
- Add more baking soda and water as needed for larger batches of coins. As a general rule, make the paste at a ratio of 3 parts baking soda to 1 part water.
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Rub the paste over the coins to make them shine. Use your fingers to spread a little bit of the paste over each coin. Work the paste into all parts of the coins. When you’re done, the coins will look shinier and the details engraved on them will stand out more.^{[27]
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- The baking soda isn’t acidic like vinegar and citrus juice solutions, so leaving the paste in place for a while is safe.
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Wash the coins off with warm water and dry them. Rinse them under a little bit of running water to remove the leftover paste. Then, pat the coins dry with a soft cloth or towel. Check the coins when you’re finished to see how shiny they look.^{[28]
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- If the coins still look a little dull, try treating them with more paste. Very old or dirty coins require the extra effort.

Expert Q&A

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How would I clean oxidized copper coins?

Alicia Sokolowski
Green Cleaning Specialist
Alicia Sokolowski is a Green Cleaning Specialist and the President and co-CEO of AspenClean, a green cleaning company in Vancouver, British Columbia. With over 2 decades of experience, Alicia specializes in creating a healthier, green alternative to chemical-based cleaning products and services. AspenClean develops and manufactures its own line of 100% Natural, EcoCert® certified, and EWG verified™ cleaning products. AspenClean’s glass cleaner was voted Parent’s Green Pick 2020 by readers of the Parents’ magazine. Alicia holds a CPA designation and a Bachelor’s degree in Commerce and Finance from the University of Toronto.

Alicia Sokolowski

Green Cleaning Specialist

Expert Answer

Mix 3 parts baking soda with 1 part vinegar. Apply the paste with a microfiber cloth and rinse it off with water. Dry the coins with a microfiber cloth to give them that extra shine!

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Tips

Cleaning a coin can significantly reduce its value, warns Hockley. He says to always get your coin appraised and valued by a coin expert before deciding to clean it.^{[29]
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Expert Interview}

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Often, the safest way to clean a coin is to send it to a professional. Numismatists and some coin collector organizations may offer these services.

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Warnings

Avoid rubbing or scrubbing valuable coins. Rubbing or scrubbing a coin (even with non-abrasive liquids) can leave microabrasions on your coin and severely reduce its value, or even eliminate its collectable value.

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Acids wear away copper, so exposing a coin to vinegar and other products can cause permanent damage. Monitor coins carefully and rinse them with clean water as soon as possible.

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