How to Clean Coins Without Damaging Them

Not using proper cleaning methods will permanently damage your coin. Read on to learn how to clean coins safely and easily here.

Is your challenge coin in need of a good scrubbing? Be careful with what you use to clean it because it can cause irreversible damage to your coin. In this guide, we’ll show you how to clean coins without damaging them.

There are over 20.4 million American veterans. Along with them come more military challenge coins. You likely received a challenge coin too, whether you served the army, air force, or another branch.

The customs of the challenge coin remain different for every branch, team, and unit. However, there is one practice that all these divisions keep. That is the proper maintenance of these coins.

Read on for ways to clean your challenge coin without scratching it or erasing its colors.

1. Why Clean Your Coins?

The military challenge coins are medallions that symbolize the unit or team you were a part of. Others get a challenge coin in recognition of a special achievement. No matter which one you earned, these coins are worth keeping and maintaining.

Like guns, maintaining your military challenge coins includes cleaning them. The typical go-to cleaning method is to wipe the challenge coin with a cloth. However, neither dry nor wet cloth is enough to get all the built-up dirt out of the metal’s surface.

Studies show some coins contain disease-causing pathogens. Those pathogens include E. coli, salmonella, and staphylococcus aureus. Consider how often you have your challenge coin with you and where you place it when challenged.

When you’re cleaning your coins, it’s important to preserve their patina. This is the finish of the coin, also the topmost protective layer of the coin. Depending on the military branch or unit, your coin’s finish may be of brass or gold.

Other metals used as the patina for challenge coins are silver, nickel, copper, and bronze. Those with color may include soft or hard enamel. Other coins have colored epoxies, which are more resilient and scratch-resistant than metals.

When you’re cleaning your coins, it’s important to consider which metal makes the finish. This lets you know what cleaning agents are safe to use for your challenge coin. Some methods of cleaning may work for coins with gold surfaces but not with silver, for example.

2. What to Avoid as Cleaning Agents for Coins

Before we talk about cleaning your challenge coins, allow us to point out what you shouldn’t clean your coins with. This way, you cross these out of the list as possible coin-cleaning agents. Better to be sure, especially since challenge coins have important symbolism.

Never use acid dips and acetone to clean your coin. It’s also a good idea to avoid metal polish. This also includes avoiding household cleaners on your coins.

If you have silver dip cleaners or silver polish, don’t use them. Even if you have silver challenge coins, it may be too harsh a chemical for your challenge coin.

These chemicals will cause abrasions or reactions with the metal of your coin. The damage that these abrasive chemicals cause to your coins is irreversible. Abrasive cleaners can also scratch the coins.

3. How to Remove Stubborn Dirt 

Adhesive substances like glue and cement can stick to your coin. While it’d be fine if it were on a currency coin, it isn’t as fine on a military challenge coin. Over time, these adhesive substances can hold dirt and rot. Be careful with how you remove adhesive dirt.

One way to do it is to use olive oil to soften up the dirt. This is an ideal solution for coins that have collected years’ worth of dirt over adhesives. This is the answer to remove hard-to-reach dirt in the coin’s engravings.

After you soak the coin in oil, use a soft toothbrush to get the dirt off. If the olive oil isn’t enough to wash away the dirt, the next step takes a bit of physical force. A small skewer can also help remove dirt buildup in engravings.

When you resort to this step, make sure you pry out the dirt with care. Using brute force to peel off the adhesive dirt can cause scratches. To avoid this, keep your challenge coin safe from future contact with adhesives.

4. Use Olive Oil

Speaking of dirt removal, olive oil works wonders in separating the dirt from the metal of challenge coins. If you ever wanted to know how to clean coins in the ancient times, it was with the olive oil method. This method worked for most metal possessions and those made of delicate metals.

This is the perfect way to clean challenge coins, especially those with layers of dirt buildup on it. Take your grandfather’s challenge coin that went unmaintained for decades, for example. As a note, avoid using virgin olive oil on bronze challenge coins since it can tarnish the metal.

Take a bit of olive oil and let it soak up the dirt on the coin for a week or more. Notice if the oil color changes in that weeklong or weeks-long soak. If it does, that means you need to change the oil from dirt-saturated to fresh.

For most challenge coins, it’s fine to give it a few days to soak in the oil. Often, challenge coins get great care and maintenance.

When you’re done soaking the coin in olive oil, give it a gentle clean with dish soap and water.

5. How to Clean Challenge Coins with Distilled Water

The safest way to clean challenge coins is by running water. However, if running water doesn’t work, distilled water can help remove persistent gunk in your coins. Distilled water is gentle in removing gunk and it won’t affect the color of the metal.

Dip the coins in distilled water for at least 24 hours. If you’re cleaning several challenge coins, they shouldn’t be in contact with one another. After a full day of dipping in the distilled water, take a soft toothbrush to scrub the gunk out.

If you still see gunk on the surface of the coin, get fresh distilled water to dip it in. Let the coin soak in the water for another day. Brush the coin again, rinse, and finally let it air-dry.

6. Clean Challenge Coins with Soap Water

You’ve tried the distilled water method yet grease remains on your challenge coin. In that case, increase the abrasiveness of the solution a tiny bit with soap. When you choose the soap, use weak soap with no acidity.

Minimizing the acidity of the soap will keep the soap water “soft” and gentle on the coin. If you use harsh dish soap, there’s a chance that the solution becomes too abrasive for the coin. It can peel off the color along with the dirt buildup.

Soak the greasy coin in the solution. While it’s in the soapy water, rub it with a soft toothbrush. Be gentle and patient in cleaning it.

Soon, you’ll see the grease and gunk separating from the surface of the coin. Rinse the coin and let it air-dry. If some gunk remains, repeat the process.

7. How to Clean Coins with Water Softener

Do you notice how sometimes your drinking glasses become cloudy? This is due to salts and mineral buildup in the water. The same thing can happen to your military coin.

Often, you’ll see this in the surfaces of coins left submerged in the water for too long. This kind of mineral buildup isn’t going away with soap. If you try using solutions that are too abrasive, there’s a chance of peeling off the color and the buildup.

What you need in these cases is a “soft” water solution. You can do this by adding dishwater products. One good example is Calgon.

With a soft water solution, it’s possible to remove the buildup without having to scrub too hard at the coin. As a note, make sure to dip your challenge coin in the solution for only a minute or two. If you dip your coin in the solution for too long, you might damage its outer layer too.

8. Wash Challenge Coins with an Isopropyl Alcohol Bath

Let’s say water and soap aren’t enough to remove grease from your coin. An alternative solution is isopropyl alcohol. This solvent has a mild acidity level and it’s a universal solvent.

Clean coins with mild dirt buildup in this method. All you need is to mix isopropyl alcohol and water in equal amounts. Let the coin soak in the solution for a couple of hours at the least.

When you’re done, rinse the coin with plenty of water. As much as possible, avoid doing this method with challenge coins made with gold finish. The soap and water method is still the best way to clean challenge coins with gold patina.

Keep Your Coin Ready for Coin Checks

Learning how to clean coins without damaging them isn’t an issue if you follow these useful tips. You can keep them nice and shiny over the years!

But why stop here when there’s more to learn about challenge coins? If you plan to read more about where you can get custom coins, check out our other guides today.