Surface Alterations

Posted by Skip Fazzari, Authentication Consultant to NGC, on 4/17/2008

Skip Fazzari explains two chemical processes that have bedeviled the coin world in recent years.

Since much of coin grading depends on eye appeal, anything that can be done to a coin to improve its “look” may increase its grade. Coin “doctors” have been at work for decades trying to improve how coins look, by both chemical and mechanical means. The results of their work have improved over time due to the use of better techniques and substances.

The first major surface alteration I encountered as a professional authenticator was called “whizzing.” I learned that whizzed coins were made by buffing a coin’s surface with a rotating metal brush. We distinguished whizzing from other forms of mechanical alteration, such as polishing and buffing, by the presence of an upturned ridge on one side of the coin’s design. A carefully whizzed high-grade coin could be very beautiful and deceive a collector into believing that they were getting a gem coin at a low price. Whizzed coins are still in the market, but they are generally found in the backwaters of numismatics, such as flea markets and mail order. Although this technique is used to alter coins is less common than in the past, modern fakers have improved the process so that it is less easy to detect.

Sometime around 1984, I began to see a more unusual alteration. This time, it was a chemical process much different from the widespread practices of “thumbing” and “waxing,” which almost anyone could do. Coin doctors were electroplating both DMPL and PL Morgan dollars to enhance the cameo contrast between their mirror-like field and frosty relief. For their first attempts, the coating was fairly thick and would scrape off easily using a toothpick. Later examples had a much thinner coating that did not come off. We were able to detect this type of alteration by a buildup of the plating material in the recesses of a coin’s design and the unnatural appearance of bagmarks that were covered with the coating.

Soon afterward, another extremely deceptive alteration was discovered that plagued the hobby for years. Coins were seen with a “putty-like” substance covering bagmarks, especially on the raised parts of the design. The material used for the alteration was dissolved in a volatile “carrier,” which evaporated to leave a cloudy film on the coin’s surface. The film covered marks on the coin, making them less noticeable. Occasionally, the liquid carrier would flow onto the field at the edge of the relief, which gave the altered coin an unnatural “look.” Any of this overflow and the covered marks under the coating on the relief is usually a give-away that a coin has been altered by this method.

Coin “doctors” will continue their quest to “pass” an undetectable alteration. Your best protection against buying an altered coin is to have any suspicious coins checked by professional graders at a major grading service.

This article was previously featured in Numismatic News.