Die polishing creates scratches on the surface of the die, which become raised marks on the coins. Coin cleaning creates scratches that are depressions on the surface of the coin. Online photos (especially closeup shots) sometimes make it difficult to distinguish recessed marks from raised marks.
In the 1960s, it was common to see silver coins cleaned with baking soda and copper coins cleaned with pencil erasers. Many of those coins are still on the market.
That's where it's helpful to study patterns of die polishing for each coin series, and for particular dates and mints within those series, too. The PCGS population report galleries are a valuable tool for doing this. When you see the areas and types of die polishing for the series and for the dates and mints of interest, scratches in photos
outside of those areas will catch your eye quickly.
There are some coin series that can have extreme die polishing that at first glance looks like cleaned coins.
Buffalo nickels are notorious for heavily abraded dies, especially the branch mint coins. Lincoln cents during the 1920s through mid-1940s have some years with exceptionally abraded dies (1922-D, 1924-D, 1934, and 1941 are a few examples). Coins struck shortly after the die abrasion can be mistaken for cleaned coins in photos.
One thing to look for to distinguish abraded dies from cleaned coins is the point where the design begins and the field ends. On one side of the central device, the die abrasions will have a gap, where the wire bristles skipped over the edge before striking the surface again in the recessed area of the die. On the other side of that device, the bristles may have a small skipped area just on the field beyond the edge. Another thing to look for is the shape of the scratch. Die polishing tends to be straight lines or "J" shaped lines (like a J-stroke when paddling a canoe). Coins cleaned with abrasives will tend to have scratches running parallel to and on the raised devices, rather than skipping a portion of the devices. They also will have thumb-sized areas of scratches heading in different directions.
Like you said, playing with the photos helps. Color saturation, exposure, and contrast tools are some good detective friends.
Just a couple thoughts.
Posted 06/19/2025 6:03 pm
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