Why Strange-Looking Coins Are Often Just Damaged

One of the most common misunderstandings we encounter at a coin shop is the assumption that every unusual-looking coin must be a mint error.

Technically, the distinction is very important.

A mint error is something that happened while the coin was being manufactured. Post-mint damage, often abbreviated as PMD, is anything that happened after the coin left the Mint.

A coin can look strange, dramatic, or completely different from an ordinary coin without being a genuine mint error.

People Do Strange Things to Coins

Coins circulate for years or decades. During that time, people handle them, alter them, damage them, use them in projects, turn them into jewelry, and sometimes simply experiment with them.

We have seen coins heated with blowtorches until bubbles formed in the metal. We have seen coins squeezed in vises, flattened, hammered, bent, drilled, polished, filed, clipped, chemically treated, and rolled around the edges.

Coins are sometimes damaged in factories, workshops, garages, garbage disposals, vending machines, washing machines, industrial equipment, and countless other places.

Eventually, some of those coins make their way back into circulation. Another person receives the coin, notices that it looks different, and begins wondering whether it is rare.

A Strange Coin Is Not Automatically an Error Coin

The first question should not be, “What kind of error is this?”

The first question should be:

Could this have happened after the coin left the Mint?

A drilled hole is not a mint error. A coin squeezed in a vise is not a mint error. A torch-created bubble is not a mint error. A coin with an edge that was rolled, ground, hammered, or altered after manufacture is not a mint error.

These are damaged coins.

That does not mean they cannot be interesting. Some damaged coins have unusual appearances or unknown stories behind them. However, unusual does not automatically mean rare, valuable, or collectible.

Why Internet Searches Can Be Misleading

The internet often pushes people in the wrong direction.

Someone may search for phrases such as “quarter with strange edge,” “coin with raised bubble,” “clipped coin error,” or “penny with unusual shape.” Search results frequently lead to articles, videos, auction listings, and social-media posts about valuable errors.

What those searches usually do not ask is whether someone used a hammer, vise, torch, grinder, drill, press, or another tool on the coin after it entered circulation.

Instead, the search results may confirm the person’s original suspicion that the coin is an error. After reading enough articles or watching enough videos, it becomes easy to believe that every unusual characteristic must have originated at the Mint.

This is similar to the misleading coin values people often encounter online. Asking prices, dramatic headlines, and unusual auction results can create an unrealistic impression of what an ordinary coin is actually worth. We discuss this problem further in our guide, Why Coin Values on the Internet Are Often Misleading.

Could the Mint Actually Have Made It?

Authenticating an error requires more than noticing that a coin looks different.

The unusual feature must make sense within the minting process. A knowledgeable dealer or error specialist considers how coin blanks are produced, how dies strike coins, how collars shape the edges, and what can realistically happen during production.

If there is no reasonable way for the Mint’s machinery to have caused the feature, post-mint damage becomes the more likely explanation.

This is one reason experience matters. After handling large numbers of coins, dealers become familiar with both genuine minting abnormalities and the many forms of damage coins acquire later.

You can learn more about common terminology used in the hobby on our Numismatic Terms page.

Clipped Coins and Altered Edges

Clipped coins are a common source of confusion.

A genuine clipped-planchet error occurs when part of the metal blank is missing before the coin is struck. However, people can also cut, grind, file, or clip coins after they leave the Mint.

The two may look similar to someone who has not handled genuine examples.

Rolled edges are another common form of post-mint alteration. A person may repeatedly press or roll the edge of a coin until it becomes thicker, narrower, smoother, or unusually shaped. That does not make it a Mint error, even though the finished coin may look very different from a normal example.

Holes, Bends, Heat and Pressure

Coins with holes are extremely common. Some were used as jewelry, attached to keychains, sewn onto clothing, mounted, nailed to objects, or used in crafts.

Bent coins may have been caught in machinery, intentionally bent with tools, or subjected to heavy pressure.

Heat can create discoloration, warping, surface bubbles, softness, or unusual textures. Chemical exposure can remove metal, change the color, roughen the surface, or produce patterns that may look unusual under magnification.

None of those characteristics automatically indicates a Mint error.

Damage Can Sometimes Look Very Convincing

Some post-mint damage is obvious. Other damage can be surprisingly convincing.

A carefully altered coin may look like an off-center strike, clipped planchet, missing design element, doubled image, unusual rim, or defective surface.

There are also counterfeit and intentionally altered coins made to deceive collectors. Those are a different issue from accidental damage, but they demonstrate why appearance alone is not enough. Our article Counterfeit Coins Are More Common Than Most People Realize explains more about that side of the market.

Do Not Try to Repair or Clean the Coin

If you find a strange-looking coin, do not polish it, scrape it, clean it, bend it back, file the edge, or attempt to remove discoloration.

Cleaning or altering a coin can make identification more difficult and may permanently reduce its value. Read Why You Should Never Clean Coins Before Selling Them before attempting to improve the appearance of an unusual coin.

It is usually best to leave the coin exactly as you found it.

What Coin Dealers Look For

Coin dealers are looking for errors that are dramatic, recognizable, explainable through the minting process, and supported by genuine collector demand.

When a significant error appears, an experienced dealer can determine whether professional authentication or grading makes financial sense. A major error may need to be submitted to a recognized grading service and marketed to collectors who specialize in that material.

Minor damage and unexplained alterations are different. A coin shop generally cannot spend extended periods researching every strange mark on a common coin, especially when the feature is likely post-mint damage.

Our numismatic coin experts regularly evaluate U.S. coins, world coins, paper money, certified coins, and entire collections.

Unusual Does Not Always Mean Valuable

A damaged coin can still be unusual. It may even be interesting.

However, the numismatic market generally distinguishes very clearly between genuine mint errors and damage that occurred afterward.

A genuine error was created during manufacture. A damaged coin acquired its unusual appearance later.

That technical distinction can determine whether a coin has a substantial collector value, a small novelty value, or no premium beyond its ordinary value.

Have a Strange Coin?

If you have an unusual coin and would like an experienced opinion, you are welcome to bring it to Oakton Coins & Collectibles for an in-person evaluation.

We do not make purchase offers from photographs because images often fail to show important details involving surfaces, edges, weight, metal composition, and evidence of alteration.

We are located in Skokie and serve collectors and sellers throughout Chicago and the surrounding suburbs. Walk-ins are welcome during regular business hours. Learn more about selling coins, view our location and hours, or browse our complete collection of coin and precious-metal selling guides.

The most important thing to remember is simple:

Not every strange-looking coin is a mint error. Sometimes it is simply a damaged coin that had a very unusual life after leaving the Mint.