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Not All Error Coins Command Big Money
By Ken Potter, Numismatic News
May 09, 2013

This article was originally printed in Numismatic News.
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If you have questions about error coins, you are not alone. Many are asked over and over again. My experience at a recent show helps highlight some of them.

I attended the Michigan State Numismatic Society Spring Convention April 19-April 21 where I offered free error-variety coin examination “answerman” services and shot photos of some of the coins that came in.

Gary Yost of Michigan showed up with 1943-D zinc-plated steel cent with the “3” of the date completely missing. The cause of this error is a filled die or what others might call a “Strike Through” error. In this case, the offending material that clogged the cavity of the “3” in the die was most assuredly what I call “Mint Goop” – an accumulation of grease, oil, dust metal filings and other contaminants that build up on and around coining presses, dies and other tooling.

Due to gravity, such goop can begin to work its way down into the dies. Most frequently, it will affect the areas closest to the rim first before either moving inward to affect more areas of design or dissipating. As such, it is not at all unusual for me to see two or three coins at a show with a missing last digit or two of the date (or missing other elements that are close to the rim).

When collectors get excited about the last digit (or two) being missing, they often think the Mint forgot to include these on the die and as such it is some form of rare die variety.

Such is not the case and since errorists prefer to have a date showing on most errors and prefer far more extensive areas to be “filled” on examples of this error type before considering them of any particular commercial value, those with a missing last digit are generally considered “minor errors” with a value of maybe 50 cents to $1 at best.

The only way we know the full date of Yost’s coin is because it is a steel cent only made in 1943. This one redeeming factor could make it of greater than average value for this type of error coin.

Eric Andrew of Michigan submitted another Strike Through error that represents a relatively small but very noticeable bit of rather solid Mint goop that dropped below Miss Liberty’s extended right arm on a silver American Eagle. In this case the Mint Goop is “retained” with the coin and the bit that flaked away just below the dark area shows that part of the design is shiny rather than of the normal satiny finish thereby authenticating the error. Nonetheless, it is not a particularly large Strike Through so its value, while debatable, would not fall into the three figure range.

Jim Doctur of Ohio brought a 1983-D Lincoln cent that exhibited plating blisters on the surface of the coin. Most of the blisters are quite moderate with just a few under Lincoln’s chin. However one pronounced blister shows as a diagonal slash-like aberration across Lincoln’s face down into the field heading toward the date.

While most plating blisters appear more or less round under moderate magnification, some are long and thin like this one. While platting blisters are a true error they have never caught on with collectors and as such they only carry educational value unless they are large like this on a proof coin where they might have a nominal value of a few dollars.

The cause of this error type is contamination of the electrolyte used in the barrel plating process that in time causes a condition known as “foaming.” At this point anti-foaming agents need to be added to the solution or it needs to be replaced but invariably a number of coins exhibiting this condition get out of the Mint every year.

Our final coin is from Mark Van Allen of Michigan who brought an example of die deterioration doubling on a 1989-D Lincoln cent.

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Die Deterioration Doubling on dies that strike zinc-plated planchets, (those from about mid-1982 through present), manifests itself differently than on dies that struck the solid copper alloy planchets of earlier years. This is due to the difference in the wear on the dies between solid brass or bronze versus copper-plated zinc. Additionally, the copper plating flows at a different rate than the zinc core and thus the unusual effect of raised ridges around the rims, some distortion of the fields and doubling most apparent in the final two or three digits of the date. The different metal flow rates between the copper plating and zinc core has also exposed the zinc core to the right of the mintmark due to the geometry of the Denver mintmark being punched into the die causing the copper to split away and be stretched toward the rim.

While die deterioration doubling is a legitimate die variation, this form of doubling is not generally considered collectible from any era or denomination. No grading service recognizes it nor do any die variety listers catalog it. DDD is considered a “normal” result of die use. This coin was submitted to me at the Polish American Numismatic Society Spring Show held a couple months before the Michigan State show.

Even though the doubling is almost as strong on the “8” as what you might find on a doubled-die cent, the cause is different and because it is created randomly by the production process, no two examples are quite identical.

On the valuable doubled-dies like the 1955 cent, the doubling is on the die itself that strikes the coins and every coin struck by it shows identical doubling. That is why populations can be counted and verified. There is no other cent identical to the 1989-D shown here.

Ken Potter is the official attributer of world doubled die for the Combined Organizations of Numismatic Error Collectors of America. He also privately lists other collectible variety types on both U.S. and world coins in the Variety Coin Register. More information on CONECA or how to get a coin listed in the Variety Coin Register may be obtained by sending a long self-addressed envelope with 65 cents postage to P.O. Box 34, Stockbridge, MI 49285, or by contacting him via email at An educational image gallery may be viewed on his website at

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