Why Does Cleaning Coins Devalue Them?

Coins pass through many hands, and they have a tendency to grow unpleasant coatings. However, collectors are told that cleaning them hurts their value. So, why does cleaning coins devalue them?

Cleaning coins devalues them because it introduces microscopic damage. If you clean a coin, you’re extremely likely to corrode it, scratch it, or wear down its details. You’ll also remove any toning or patinas. A damaged coin is a lesser quality coin and is, therefore, worth less.

In this article, I will explain why you can’t clean coins without devaluing them, why it’s so risky, and how appraisers know when a coin has been cleaned. I’ll also talk about when you should clean coins, why you can’t restore them afterward, and why a coin’s toning or patina shouldn’t be removed. Read on.

Can You Clean Coins Without Devaluing Them?

You can clean coins without devaluing them, but unless you soak them in water or use gentle cleaners such as witch hazel, the chances that you’ll damage and devalue your coins are extremely high. So, it’s not recommended you try to do so unless your coin is caked in dirt or is otherwise unidentifiable.

Coins are evaluated by an appraiser before they are sold on coin markets, and part of what determines their price is their quality. Metal polishes or home cleaning remedies are corrosive, and brushes or metal wools are equally as damaging, making cleaning your coins in traditional ways detrimental to their quality.

Some gentle cleaners exist, such as witch hazel. However, even gentle cleaning can damage a coin. It’s okay to clean your coins in certain circumstances, but even then, it’s essential to avoid scrubbing them in order to preserve their quality.

All in all, cleaning your coin in any capacity is risky, and it’s a practice best avoided if you can help it.

Why Is Cleaning Coins So Risky?

Coins are made of metal, which is a tough material. So why is cleaning coins so risky?

Cleaning coins is risky because coins — especially old ones — are more fragile than they appear. Their surfaces can become scratched or worn down by brushes and scrubbing, and metal creates chemical reactions very easily. Even storing your coins in paper can cause damage, never mind cleaning them.

Metal is typically thought to be durable. But in reality, it’s prone to microscopic corrosion, wear, and chemical reactions. In most cases, any damage on a metal object can be seen with the naked eye. 

But coins are looked at under a magnifying glass and are put under a lot more scrutiny due to their status as a collector’s object. Valued traits in jewelry or silverware aren’t the same as in coin collecting. Collectors value authenticity and history, and simply being shiny isn’t enough to justify any damage.

When coins are assessed by an appraiser before sale, they’ll have these values in mind. If they see that you’ve cleaned your coins, they’re likely to devalue them in proportion to the damage your cleaning has caused, which can make it hard to recoup the financial costs incurred when you bought it.

How Do Appraisers Know a Coin Has Been Cleaned?

Appraisers know when a coin has been cleaned because they see microscopic forms of damage when they look at it under a magnifying glass. This includes scratches, corrosion, tiny holes, discoloration, and other forms of damage that might come from cleaning or improper storage.

Appraisers tend to be knowledgeable and experienced, especially if they’re reputable. They inspect many coins in a day and have likely seen every form of damage at least a few times before. It’ll be hard to pull the wool over their eyes, and I don’t suggest you try because, under a magnifying glass, damage on a coin isn’t that hard to spot.

If you have your own magnifying glass, which most coin collectors should, you can even inspect your coins for any damage yourself. Each scratch, hole, discolored spot, or other anomaly counts against your coin’s value unless it’s toning or a patina. 

If you’re up to it, it’s a good idea to get into the habit of examining your coins yourself. It can be another way to enjoy your collection, and you’ll likely learn much more about your coins and collecting in general over time.

That said, it’s worth noting that most coin appraisers will charge you to value (or devalue) your coin collection. But if you don’t want to spend money, you can check out my article on how to get your coin collection graded for free: How to Get Your Coins Graded for Free (5 Steps)

Can Appraisers Tell if You’ve Used Gentle Cleaners?

Appraisers might see that you’ve used gentle cleaners, especially if you’ve rubbed or scrubbed your coins. However, substances like witch hazel are a lot less likely to damage your coins, and if they do, the damage is less likely to be serious. It depends on how you’re cleaning your coins.

If your coin has a patina, for example, rubbing or scrubbing your coin with witch hazel can still dislodge parts of it, damaging it in the process. Whereas if you soak your coin in witch hazel and then gently rinse it in water, the chance of that happening is a lot less.

How you clean your coins matters. Even with gentle cleaners, it’s suggested that you simply soak your coins in them and rinse them off. Anything more than that risks damaging your coins, so try not to stray too far from the beaten path. This is one situation where innovation isn’t a good idea.

Destructive Cleaning vs. Non-Destructive Cleaning

In truth, there are two different ways to clean coins: destructive and non-destructive.

Destructive cleaning is just that — destructive. It makes use of corrosive substances to clean coins and therefore damages them. Non-destructive cleaning does the opposite. It uses substances that are inert and won’t damage or react with your coins’ surfaces.

If you want to learn more about destructive and non-destructive cleaning, check out this article by the Edmonton Numismatic Society, which goes into the subject in detail.

Are There Any Situations Where You Should Clean Coins?

There are only a few situations where you should clean your coins. Unless your coins are covered in dirt to the point where they’re unrecognizable or have had damaging or corrosive substances spilled on them, you shouldn’t clean them.

Sometimes, when you find coins in the ground using a metal detector or when you simply find them in an unconventional place, they may be covered in dirt or other undesirable things. In cases such as these, soaking them in water overnight and then gently rinsing them off is enough to get rid of any dirt.

In other situations, harmful substances might be spilled on or otherwise come into contact with your coins. But in these cases, rinsing them off in water as soon as possible is also the fix. While you can use gentle cleaners like witch hazel or olive oil, in most cases, water will do the trick.

Can You Restore Coins That Have Been Cleaned?

All this talk of avoiding cleaning is well and good, but what if you’ve already cleaned your coins? Can you restore coins that have been cleaned?

You can’t restore coins that have been cleaned. Cleaning coins results in a loss of metal, and short of melting down the coin and re-minting it, there’s no way to add more. Byproducts such as green slime from PVC exposure can be wiped off, but most other forms of damage are permanent.

Does Removing Toning Devalue a Coin?

While we’re on the topic of restoring coins, does removing toning devalue a coin?

Removing toning can devalue a coin, depending on which coin it is. Some coins, like silver dollars, are worth much more if they are toned. However, others, such as Lincoln pennies, don’t need to be toned. It’s important to do research on your coins before you do any cleaning.

In coin collecting, tarnish is known as toning. It’s a desirable trait on silver dollars or other silver coins. In fact, silver dollars are worth less if they don’t have an iridescent coating on them. Along with patinas, some people seek them out specifically for their appearance.

Does Removing a Patina Devalue a Coin?

Removing a patina from a bronze or copper coin will devalue it, especially if it’s ancient. Patinas are sought-after traits in coin collecting, and removing them removes valuable evidence of your coins’ age and history. If your coins have patinas, don’t try to remove them.

Ancient bronze or copper coins from equally ancient places such as Rome can sometimes go for thousands of dollars, and part of the reason why is that they look as old as they are. If they didn’t have their corroded patina and looked shiny and new, they would be considered knock-offs.

It’s unlikely that you’ll get an ancient coin that clean without completely removing the image on its face, but because their age and authenticity are valued, it’s best not to try to remove a patina in any capacity.


Cleaning coins is risky and will introduce microscopic damage as well as remove toning and patinas, which appraisers see and devalue for. You should only clean coins in a few specific situations, and even then, you should use gentle cleaners like witch hazel and olive oil because cleaned coins cannot be restored.

Alexander Picot

Alexander Picot is the principal creator of DiscoveryPit.com, a website dedicated to tips on finding and collecting precious items. Inspired by reading countless adventurer reports from the oldtimers, Alex is passionate about discovering hidden treasures and loves to share his experience with the rest of the world.

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