Your Complete Guide to Cleaning Ancient Coins

Ancient coins offer a window into the past. However, they are often dirty when you acquire them. If recommended by an appraiser, you can clean them while preserving their beauty and value. There are many options available for cleaning your coins, depending on the level of dirtiness. In this article, we’ll show you when it’s acceptable to clean an old coin and the safest ways to do it, with expert input and advice from numismatics expert Max Hockley.

Note: If you think a coin might be valuable, do not clean it unless recommended by an appraiser. If you unknowingly clean a valuable coin, you’re likely to damage it and diminish its value. They’ve been dirty long enough—they can wait another few days!^{[1]
X
Expert Source

Max Hockley
Numismatics and Precious Metals Expert

Expert Interview}

An Overview On Cleaning Ancient Coins

Never clean an ancient coin unless recommended by an appraiser. If you do clean a coin, numismatics expert Max Hockley recommends rinsing it under warm, distilled water first. If that doesn’t work, you can try gently rubbing the dirt free or add a bit of dish soap and scrub the coin with a toothbrush.

Section 1 of 7:

When should you clean an ancient coin?

Download Article

1
Only clean an old coin if it’s determined not to be valuable. According to Hockley, it’s absolutely essential to get your coins appraised before attempting to clean them. “The value of a coin is very dependent on its condition,” Hockley explains. “And to a novice…they associate ‘shiny’ with ‘good condition.’ But that’s not how coin collectors see it.”^{[2]
X
Expert Source

Max Hockley
Numismatics and Precious Metals Expert

Expert Interview} In fact, cleaning an ancient coin actually decreases its value, so you should only do it if an appraiser gives you the go-ahead.
- The Bottom Line: There’s a high chance of damaging a coin if you clean it yourself, so don’t do it unless the coin has been appraised and doesn’t have any real value.
Meet the wikiHow Expert

Max Hockley is a numismatics expert and the creator of the Silverpicker YouTube channel, with over 15 years of experience in collecting coins.
2
Clean a low-value coin to make it more visually appealing. “Maybe you want to clean a coin because you’ve already determined that it’s not a diamond in the rough. It’s a coin that’s worth $40, and if it’s cleaned, it’s worth $22,” says Hockley. “You want to use it as jewelry. It was your grandfather’s, and you want to put it in a frame with a picture of him… There are a million reasons why you might want to clean a coin to make it more visually appealing.”^{[3]
X
Expert Source

Max Hockley
Numismatics and Precious Metals Expert

Expert Interview} In these cases, it’s probably okay to go ahead and do it.
- Basically, if a coin really isn’t special or worth a lot of money, but you still want it to look all shiny and nice, you can clean it.
Advertisement
3
Clean a coin if you find it on the ground. According to Hockley, there’s one category of coin that is completely acceptable to clean, even from a collector’s perspective—and that’s coins pulled out of the ground. When you find a coin in the ground (say, with a metal detector, or even just by pure luck), and it’s all corroded to the point that you can’t even tell what it is, there’s nothing wrong with cleaning it.^{[4]
X
Expert Source

Max Hockley
Numismatics and Precious Metals Expert

Expert Interview}
- You can’t sell a coin if you can’t even tell what it is, which is why (gently) cleaning coins recovered from the ground is okay.

Section 2 of 7:

Cleaning Ancient Coins with a Simple Washing

Download Article

1
Rinse the coin with water. “First thing you want to do is wash [the coin] with running water, or in a bucket,” says Hockley. “Do not rub it, because when you rub the dirt off, you’re pulling whatever little rocks or bits of sand or dirt that are trapped in that mud across the coin, and you’re going to scratch it.”^{[5]
X
Expert Source

Max Hockley
Numismatics and Precious Metals Expert

Expert Interview} Hold the coin under the water and let the dirt come off naturally.
- Additionally, it’s best to use distilled water; tap water has minerals and ions that can disrupt the cleaning process.
2
Rub the coin gently once dirt starts coming off. Even though Hockley cautions against rubbing the coin at first, he says that you can do so once you’re able to see a little better under the water.^{[6]
X
Expert Source

Max Hockley
Numismatics and Precious Metals Expert

Expert Interview} Just rub the coin very gently while it’s in the water to get more caked-on dirt off, and try to be careful not to scratch anything in the process. Cleaning coins is a really delicate process!
- Be patient. It’ll probably take time to clean an old coin, especially when taking precautions not to damage it.
3
Wash the coin with dish soap and water. If soaking in water alone hasn’t helped, you can try using a little bit of mild detergent or dish soap, according to Hockley.^{[7]
X
Expert Source

Max Hockley
Numismatics and Precious Metals Expert

Expert Interview} At this point, you should still just be using your fingers to gently scrub while holding the coin under warm water. See if lightly scrubbing it after applying detergent or dish soap clears away more of the dirt and grime.
- When cleaning coins, remember to try the least abrasive methods first. For instance, only use soap if a water rinse and gentle rubbing don’t work, and so on.
4
Use a toothbrush to scrub the coin. If soap alone isn’t quite adequate, you can take a toothbrush with a little bit of the dish soap (or baking soda, according to Hockley) and, with very light motions, rub the coin to get the grime off.^{[8]
X
Expert Source

Max Hockley
Numismatics and Precious Metals Expert

Expert Interview} While a soft toothbrush is okay to use, never use a metal brush—the bristles will scratch your coin and damage it.
- Hockley cautions that even washing a coin with soap and a toothbrush will diminish the coin’s value. “It’s still going to be considered a cleaned coin, and it’s going to sell less than if it were in mint state condition.”^{[9]
  X
  Expert Source
  
  Max Hockley
  Numismatics and Precious Metals Expert
  
  Expert Interview}

Section 3 of 7:

Cleaning Ancient Coins with Aggressive Washing Methods

Download Article

1
Soak the coin in olive oil. If you’re dealing with bronze or copper coins, an olive oil soak can penetrate through the grime and break it off over time. Pour olive oil into a closable container, then place your coins into the oil and close the container. You can leave the coins to soak for weeks or even months—just remember to change out the oil once or twice a month.^{[10]
X
Research source}
- After the first week, you can try scrubbing the coin with a toothbrush, or even use the above cleaning method and scrub it with dish soap under running water.
2
Use a dental pick, toothpick, or other hand cleaning tool. When using a dental pick or toothpick, don’t start scraping with the point; turn the pick sideways and use a circular motion to remove dirt and debris. A circular motion is better for your coins than moving the pick up and down or left to right. You can also try using hand cleaning tools like a plastic knife or a soft eraser, and see if those work any better.
- Remember, you should not use this method (or any cleaning method) unless the coin has no value. It’s very easy to damage the coin this way, especially if you’re inexperienced.
A microscope, a magnifying glass, or a table magnifier can help you while you clean your coin. It’ll allow you to see the coin and the details better. Different areas of the coin may need less (or more) cleaning than others, and you’ll be better able to monitor a coin to make sure you aren’t scratching or damaging it too much. Make sure you have good lighting when you’re cleaning, too.

Section 4 of 7:

Last Resort Methods for Cleaning Ancient Coins

Download Article

1
Apply a solution of vinegar and salt to your coins. Mix a solution with about 1 cup (8 oz.) of white vinegar and 1 tablespoon (33 grams) of salt. Then, place your coins (ideally bronze or copper coins) in the container with the solution and wait a few seconds; you should see the debris and dirt on them start to dissolve. After that, remove the coins, rinse them, and dry them off.^{[11]
X
Research source}
- You can also try a solution of diluted lemon juice with 50% distilled water, and let the coins soak in it for 10 minutes.
- Be very cautious when soaking your coins in chemicals. There’s a higher chance of damaging your coins this way.
2
Use electrolysis. If absolutely everything else has failed and you’re sure the coin has no value, you can use electrolysis, which involves using an electrical current to clean coins. Wrap your coin in aluminum foil, but leave the foil open around the edges a little bit. Pour malt vinegar into a shallow container and submerge the coin for 30 to 60 seconds. This will create an electrical flow between the metal and chemicals.
- After the time is up, unwrap the coin and rub it gently with your fingers to remove grime and debris.
- There is a very high probability of damaging your coin if you use this method—so, again, only do it as a last resort!

Section 5 of 7:

Cleaning Silver Coins Without Damaging Them

Download Article

Use a process called “dipping” to clean silver coins. For this process, you can use pure acetone or a product intended specifically for silver coins; Hockley notes that e-Z-est is one such product, which is commonly used and made for jewelry and coins. “Essentially, you dip the coin, you leave it in there, and then you take the coin out and pat it dry,” Hockley explains. “It will remove that ugly patina without harming the actual surface of the coin.”^{[12]
X
Expert Source

Max Hockley
Numismatics and Precious Metals Expert

Expert Interview}
- Just keep in mind that the dipping process isn’t an exact science. It may not always work, and there’s still a chance that it’ll damage your silver coins.
- However, according to Hockley, “In most cases, you could even send those [coins] in for grading and still receive a grade.”^{[13]
  X
  Expert Source
  
  Max Hockley
  Numismatics and Precious Metals Expert
  
  Expert Interview}

Section 6 of 7:

Finding a Professional Coin Cleaner

Download Article

Professionals are most qualified to clean coins without damaging them. A professional cleaner will be able to evaluate your coin and determine the safest and best techniques for cleaning it (if any).^{[14]
X
Research source} Professional coin cleaners can be found through the Numismatic Conservation Services website.
- As we’ve explained: coins will lose value after they have been cleaned. Thus, it’s best to take your coin to a professional cleaner.^{[15]
  X
  Research source}

Section 7 of 7:

How can cleaning damage a coin?

Download Article

Cleaning can scratch a coin and remove its mint luster. “When you clean [a coin], you strip away all that mint luster and…all of the patina that non-collectors would just look at as dirt,” Hockley says. “But really it’s environmental toning and patina that’s layered on top of those coins over many, many years, and that’s something that actually gives it depth and character.” From a collector’s perspective, a cleaned coin looks totally uniform and has no character!^{[16]
X
Expert Source

Max Hockley
Numismatics and Precious Metals Expert

Expert Interview}
- “Let’s say a coin that, to an untrained eye, looks kind of dirty, but actually could get a low mint state grade, like a mint state 62. That coin might be worth $1,500. But when you clean it…they no longer even grade it. It just says ‘cleaned’ on the label.”
- The “cleaned” label denotes a coin that’s effectively damaged. “And that can go from that $1,500 to $60,” Hockley explains. “The value difference is that stark.”^{[17]
  X
  Expert Source
  
  Max Hockley
  Numismatics and Precious Metals Expert
  
  Expert Interview}

Community Q&A

Search

Add New Question

Question

When buying a coin online, how can I tell whether it is genuine?

Tom De Backer

Top Answerer

These usually come with a certificate of authenticity. But unfortunately, you can never really know for sure. Forgers capable of faking coins are also capable of faking documents, after all. If you don't trust it, don't do it.

Thanks! We're glad this was helpful.
Thank you for your feedback.
If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
Yes No

Not Helpful 6 Helpful 14

Ask a Question

200 characters left

Include your email address to get a message when this question is answered.

Submit

Tips

Practice your cleaning skills on other coins before you work on your ancient coins.

Thanks
Helpful 0 Not Helpful 0
Don't attempt to clean ancient coins yourself if they have any significant value, as this will decrease their value significantly. Use gloves rather than your bare hands, store the coins in a plastic coin envelope to protect them, and get them appraised.

Thanks
Helpful 0 Not Helpful 0
Do not be tempted to use metal brushes, rock tumblers, or ultrasonic cleaners. All of these methods will result in smooth, featureless metal slugs that are worth almost nothing.

Thanks
Helpful 0 Not Helpful 0