Collecting Cleaned Coins: A Controversial but Personal Choice

Wait, collect cleaned coins? Why would anyone do that?

Well, here’s a better question: how do you know the raw coins in your collection haven’t been cleaned?

Identifying cleaned coins is a real challenge—especially when purchasing online. Photos don’t always reveal the subtle signs of cleaning, and it’s hard to tell whether the seller is unaware or simply not disclosing that a coin has been cleaned. Either way, it leaves the buyer guessing.

Why Cleaned Coins Are Often Avoided?

So why do collectors—especially seasoned collectors—tend to avoid cleaned coins?

Simply put: value depreciation.

In the world of numismatics, a cleaned coin is often considered damaged, no matter how shiny it looks. Cleaning can leave fine scratches, alter the surface, or strip away the original patina—all of which reduce a coin’s desirability and grading potential.

Then Why Do Collectors Clean Coins at All?

If cleaning devalues a coin, why do collectors still do it?

Sometimes it’s a matter of personal preference, and other times, a necessity—particularly when the coin is heavily soiled or corroded and needs cleaning to restore its appeal or prevent further deterioration.

In general, cleaning coins is not recommended. But if you’re the kind of collector who appreciates a coin for its design, history, or aesthetic—cleaned or not—that’s perfectly fine. It’s your collection, after all.

The real issue arises when a cleaned coin enters the market undisclosed. An unsuspecting buyer might believe they’ve found a gem, only to submit it to a third-party grading (TPG) service and receive it back labeled as “Cleaned”—far from the Mint State grade they were hoping for.

Is It Worth It to Buy Cleaned Coins?

That ultimately comes down to personal preference—whether it’s a disclosed raw cleaned coin or a TPG-graded coin labeled as "Cleaned."

One thing is certain: cleaned coins are often more affordable. In auctions, I’ve noticed that raw coins (presumably uncleaned) tend to command a premium over TPG-graded coins labeled as “Cleaned.” In some cases, those labeled coins don’t even sell.

Some sellers crack out coins from third-party grading (TPG) holders that are labeled “Cleaned” or given a non-numeric grade (like “AU Details” or “UNC Details”) because those labels can hurt resale value. Once the coin is removed from the slab, it’s often resold as a raw coin—with no mention of its prior grading status. If the coin has strong AU (About Uncirculated) or UNC (Uncirculated) details, it may attract a higher price from an unsuspecting buyer who assumes it's a pristine, high-grade piece.

However, if a coin is rare or highly sought after, it can still command a premium—even if it’s been cleaned. Rarity, historical significance, and demand can outweigh the cleaning stigma in certain cases.

So, if you’re a collector who doesn’t mind a coin’s cleaned status, or you're working with a tight budget and simply want to own a piece of that coin type or era, cleaned coins can be a practical and rewarding option.

How to Spot a Cleaned Coin?

Now, this can be tricky—even seasoned collectors sometimes miss the signs. But there are a few telltale clues:

1. Unnatural Color

When a coin has been cleaned—especially with chemicals—its surface may appear too bright, overly shiny, or oddly toned compared to what’s expected for its age and metal type. TPG services may flag this as “altered color,” indicating that chemical interference has changed the coin’s natural appearance.

For comparison, the next photo shows a similar coin that, to the best of my observation, remains uncleaned—showcasing its natural toning and surface.

2. Hairline Scratches from Polishing

Another sign is the presence of fine, uniform scratches that don’t match normal circulation wear. These marks often suggest the coin has been polished or rubbed with abrasive materials like cloths, brushes, or pastes. Unlike the random dings from circulation, these scratches usually follow a consistent direction, which can be a red flag.

Take this Philippine 1982 25 Piso Commemorative Coin, for example. This coin wasn’t intended for circulation, yet under raw, unedited lighting, both the obverse and reverse show hairlines with a directional pattern. I was initially skeptical that it had been cleaned, so I submitted it to NGC for grading—and to my dismay, it came back labeled as “Cleaned.”

In contrast, the next photo shows a similar coin graded Mint State—untouched and retaining its original luster.

This experience taught me how subtle—and easy to miss—cleaning signs can be, especially with coins that have reflective or proof-like surfaces.

3. Uneven Relief Edges

A helpful tip from the YouTube video How to identify cleaned coins. Is your coin cleaned and should you clean it? where Coin Guy highlights that the edges of the relief—the raised parts of a coin’s design—are often the hardest areas to clean.

When a coin has been scrubbed or polished, the flat surfaces may look bright and smooth, while dirt or natural toning often remains around the relief’s edges, creating an uneven, telltale finish.

I’ve noticed this frequently on U.S-Philippine coins—something I initially overlooked, not realizing it was a classic indicator of cleaning. It’s a subtle but telling detail—the kind of thing experienced collectors learn to recognize over time.

Always be cautious when buying raw coins that look pristine but are being sold at unusually low or suspiciously high prices. Check for signs of cleaning (hairlines, unnatural shine, uneven toning) and when in doubt, compare it with certified examples—or buy only from trusted sellers who disclose everything.

How to Clean a Coin (If You Really Have To)

Wait, clean a coin? Why would you do that?

As mentioned earlier, cleaning is generally discouraged in numismatics. But in some cases, it becomes a personal choice—or even a necessity.

Take this example: the coin below is a cleaned U.S-Philippine 1912 One Peso. When I purchased it, it was heavily soiled with greenish, blackish, and brownish residue covering the entire surface-the design was barely visible. Even the seller advised against cleaning it. But in this case, cleaning wasn’t just about looks—it was the only way to assess the coin’s condition and identify the details underneath.

A Gentle Cleaning Method I Tried

One gentle cleaning method I found online uses baking soda, hot water, and aluminum foil. It’s known for being non-corrosive and less abrasive than traditional cleaning techniques.

Here’s how I did it:

Line a ceramic bowl with aluminum foil (shiny side up).

Sprinkle baking soda generously across the bottom.

Place the coin on the foil.

Add more baking soda over the coin.

Pour hot water into the bowl until the coin is fully submerged.

After a few moments, a mild chemical reaction occurs (similar to removing tarnish from silver), and—voilà! The coin became noticeably shinier, and the design details were finally visible.

Coin Cleaning vs. Conservation

Aren’t they the same?

Well… not quite. Or maybe yes—depending on how you define the difference.

If you look it up, most sources describe cleaning as the process of removing dirt, corrosion, or buildup from a coin’s surface—often using physical or chemical means.

Conservation, on the other hand, is more focused on preserving the coin’s original surface, removing harmful contaminants without altering or damaging the coin’s metal or patina.

Let me share an example:

I had a Philippine 1982 50 Piso Commemorative Coin, freshly cut from its original packaging. When I inspected it, I noticed some foamy white residue—like moisture spots—especially on the reverse. I decided to send it to NGC for grading.

To my surprise, NGC recommended the coin for conservation. I had never tried the service before, but curiosity got the best of me (plus an additional fee, of course), so I agreed.

When the coin came back, I immediately saw the difference. It looked crystal clear—a major improvement in appearance.

Although I was hoping for a higher grade—especially since the coin came straight from original packaging—I gained a new appreciation for what professional conservation can do. It helped restore the coin’s appeal without damaging the surface or jeopardizing its integrity.

Final Thoughts: Collect What You Love

At the end of the day, numismatics is a personal journey. The most important thing is that you’re building a collection that brings you joy—whether a coin is cleaned or not.

Yes, cleaned coins come with trade-offs: lower resale value, market stigma, and grading limitations. But they also offer affordability, accessibility, and in some cases, cleaned coins can reveal sharper details and clearer design features than certain Mint State examples.

Learning how to identify and understand cleaned coins is a valuable skill that will help you become a smarter, more confident collector, and empower you to make informed decisions.

So whether you're preserving a piece of history—or polishing up something with potential—collect what speaks to you.