How to Clean Coins Without Destroying Their Value: A Collector's Honest Perspective

I've been staring at a 1943 steel penny for the past twenty minutes, wondering if I should clean it. The thing looks like it spent the last eighty years buried in someone's backyard – which, knowing its previous owner, it probably did. This internal debate happens every time I acquire a new coin, and I suspect you're here because you're facing the same dilemma.

The truth about cleaning coins is messier than most people realize. It's not just about making them shiny; it's about understanding what you're actually doing to the metal, the history, and potentially the value of these little pieces of art and commerce.

The Great Cleaning Controversy

Let me be blunt: most serious collectors will tell you never to clean a coin. Ever. They'll practically hiss at you if you mention Brasso or baking soda. And they're not entirely wrong – I've seen beautiful coins turned into worthless metal discs by well-meaning people with toothbrushes and good intentions.

But here's what those purists won't always admit: sometimes cleaning makes sense. If you've inherited grandpa's jar of pocket change and want to see what's actually in there, or if you're dealing with coins so corroded they're literally falling apart, careful cleaning might be your only option. The key word being "careful."

Understanding What's Actually on Your Coins

Before you even think about cleaning, you need to know what you're dealing with. That dark coating on your penny isn't just "dirt" – it's likely a patina that took decades to form. On copper coins, this might be a rich chocolate brown that collectors actually prize. On silver, it could be rainbow toning that adds significant value.

I learned this lesson the hard way with a Morgan silver dollar I found at an estate sale. What I thought was ugly black tarnish turned out to be what dealers call "monster toning" – the coin was worth three times more with that "ugly" surface than it would have been bright and shiny.

Then there's actual dirt, grease, and what I call "pocket gunk" – the accumulated detritus of decades spent rattling around with keys, lint, and whatever else lives in pockets. This stuff can usually come off without damaging the coin, but you need to know the difference.

The Acetone Method: My Go-To First Step

If I absolutely must clean a coin, I start with pure acetone. Not nail polish remover – that stuff has oils and fragrances that will leave residue. I mean 100% pure acetone from the hardware store.

Here's my process: I pour a small amount into a glass container (never plastic – acetone eats through most plastics like acid through paper). I drop the coin in and let it sit for about thirty seconds. No rubbing, no agitation, just letting the acetone do its thing. Then I remove the coin with plastic tweezers and let it air dry on a soft cloth.

This method only removes organic contaminants – things like tape residue, finger oils, or that mysterious sticky stuff that somehow gets on every coin that's been in a drawer for twenty years. It won't touch toning or patina, which is exactly what you want.

Water and Soap: Sometimes That's All You Need

For coins with no numismatic value – your pocket change, basically – warm water and a tiny drop of dish soap can work wonders. I fill a plastic container with distilled water (tap water has minerals that can spot the coins), add literally one drop of Dawn, and let the coins soak for a few minutes.

The trick is to never, ever rub the coins. Even with something as soft as your finger, you're creating tiny scratches that will show up under magnification. Instead, I gently swish the water around, maybe use a soft stream of distilled water to rinse, and pat dry with a microfiber cloth.

The Olive Oil Controversy

Old-timers swear by olive oil for removing verdigris (that green crusty stuff) from ancient coins. The process involves soaking the coin in olive oil for weeks or even months, occasionally checking progress. I've tried this exactly once, on a Roman bronze that was more verdigris than coin.

Did it work? Sort of. After six weeks, some of the green came off. But the coin also had this weird, oily sheen that never quite went away, no matter how much I tried to remove it. Plus, my wife was not thrilled about the container of oily ancient coins sitting on the kitchen counter for over a month. Your mileage may vary, but I'd call this method a last resort.

Electrolysis: Playing with Lightning

Now we're getting into dangerous territory – both for your coins and potentially for you. Electrolysis uses electrical current to remove corrosion and can produce dramatic results. It can also completely strip a coin of all character and value in seconds if you don't know what you're doing.

I've used electrolysis exactly three times, all on completely corroded coins that were essentially metal lumps. The setup involves a phone charger, alligator clips, salt water, and more patience than most people possess. The results were... mixed. One coin came out looking decent, one dissolved into nothing, and one sparked and made me question my life choices.

If you're thinking about trying electrolysis, my advice is simple: don't. Unless you have extensive experience and coins you're willing to sacrifice, the risk far outweighs any potential reward.

Commercial Coin Cleaners: The Good, Bad, and Ugly

Walk into any coin shop and you'll see a dozen different coin cleaning products. E-Z-Est, MS70, Coin Care – they all promise to safely clean your coins without damaging them. In my experience, they're all basically expensive soap.

The "dips" are a different story. These acidic solutions can strip tarnish from silver in seconds, leaving behind a bright, white surface. They also leave behind a distinctive appearance that any experienced collector can spot from across the room. Dipped coins have this unnatural, almost ghostly white color that screams "I've been cleaned!"

I keep a bottle of silver dip in my supplies, but I've used it maybe twice in ten years, both times on coins so tarnished they were black. Even then, I diluted it significantly and immediately neutralized it with baking soda and water.

Special Considerations for Different Metals

Copper coins are probably the most sensitive to cleaning. That brown patina is actually a protective layer, and removing it exposes fresh copper that will quickly turn an unnatural pink color. I've seen people turn valuable Indian Head pennies into bright pink disasters that look like they were spray-painted.

Silver is more forgiving, but it's also more likely to have valuable toning. Those rainbow colors you sometimes see on Morgan dollars? They can add hundreds or thousands of dollars to a coin's value. Clean them off, and you've just thrown money away.

Gold is the most stable and least likely to need cleaning. In fact, if your gold coin is dirty, it's probably not actually dirty – it might have copper or silver alloy content that's tarnished. Be very careful here.

When NOT to Clean (Which is Most of the Time)

Here's my rule: if a coin has any potential numismatic value, I don't clean it. Period. This includes:

• Any coin that might be worth more than face value
• Anything older than 1965 (when silver was removed from U.S. coins)
• Any coin with original surfaces, even if they're dark
• Coins with any kind of toning or patina
• Anything you're not 100% sure about

I once watched a guy clean a roll of Mercury dimes he inherited. They went from being worth maybe $3-5 each to being worth their silver melt value – about $1.50. That's an expensive lesson in why cleaning isn't always the answer.

The Psychology of Shiny Things

There's something deeply satisfying about taking a dirty coin and making it shine. I get it. It's the same impulse that makes people pressure wash driveways or detail cars. But coins aren't driveways.

Every coin tells a story through its surface. That wear pattern shows how it was used. That toning reveals how it was stored. Even the dirt can be historically significant – I've seen coins with soil from specific archaeological sites that added to their provenance.

When you clean a coin, you're erasing part of that story. Sometimes that's okay – nobody cares about the history of a 1995 quarter. But sometimes you're destroying something irreplaceable.

My Personal Cleaning Kit

After years of trial and error (mostly error), here's what I actually keep on hand:

• Pure acetone
• Distilled water
• A few drops of Dawn dish soap
• Microfiber cloths
• Soft plastic containers
• Plastic tweezers
• A jeweler's loupe to inspect before and after
• Most importantly: restraint

Notice what's not on that list? No brass brushes, no polishing compounds, no ultrasonic cleaners, no rock tumblers (yes, I've seen people try this), and definitely no power tools.

The Bottom Line

If you've made it this far, you're probably serious about doing this right. So here's my honest advice: unless you're dealing with modern pocket change or coins that are literally disintegrating, don't clean them. The risk of damage far outweighs any aesthetic improvement.

If you must clean, start with the gentlest method possible and stop the moment you achieve acceptable results. Remember that you can always clean more later, but you can never undo aggressive cleaning.

And please, for the love of all that is numismatic, never clean a coin before trying to sell it. Any dealer or collector will know immediately, and you'll get less money than if you'd left it alone. I see this at coin shows constantly – people who "helpfully" cleaned grandpa's coin collection and turned thousands of dollars into hundreds.

That 1943 steel penny I mentioned at the beginning? I'm leaving it alone. Sure, it's crusty and dark, but it's honest. It earned every bit of that patina through eight decades of existence. Who am I to erase that history for the sake of making it shiny?

Sometimes the best cleaning method is no cleaning at all. Your future self – and your coins – will thank you.

Authoritative Sources:

Bowers, Q. David. The Expert's Guide to Collecting & Investing in Rare Coins. Whitman Publishing, 2005.

Breen, Walter. Walter Breen's Complete Encyclopedia of U.S. and Colonial Coins. Doubleday, 1988.

Lange, David W. Coin Collecting For Dummies. 2nd ed., John Wiley & Sons, 2007.

Newman, Eric P., and Kenneth E. Bressett. The Fantastic 1804 Dollar. Whitman Publishing, 2009.

Travers, Scott A. The Coin Collector's Survival Manual. 7th ed., House of Collectibles, 2010.

United States Mint. "Caring for Your Coin Collection." United States Mint, www.usmint.gov/learn/collecting-basics/caring-for-your-collection.

Yeoman, R.S. A Guide Book of United States Coins 2023. 76th ed., Whitman Publishing, 2022.