Conservation of Modern Coins
Posted: 10/4/2002 by NGC
Even though, by their own definition, modern coins are relatively new, they can still develop many of the same problems that older coins do.
Among the list of commonly encountered problems are spotting, hazing, unattractive toning, PVC residue and improper dipping. In some cases these various problems can cover the entire surface of a coin leaving it unable to be accurately graded. These problems often originate from being stored under humid conditions or in potentially harmful containers. No matter how slight these contaminations may be, they will still have an affect on the final grade of your coin. They can occur even in the original Mint sealed packaging. It has been widely reported that recently the U.S. Mint was planning to sell off a large parcel of older proof sets. It was determined that significant portions of the sets were spotted and ultimately were not sold.
Proper conservation techniques such as those used by the Numismatic Conservation Service (NCS) can remove most or all of these types of contamination as well as many other types. It is not at all uncommon for a modern coin that would grade 67 or 68 (Mint State or Proof) due to these various problems, to grade 69 or even 70 after proper conservation. It is also extremely important to remember that several of these contaminants will continue to get worse and possibly damage the surface of the coin over time. The Numismatic Conservation Service (NCS) has spent numerous hours developing the best methods for conserving the various problems that they encounter. Please note that certain types of problems cannot be addressed through professional conservation. In these cases, surface damage has occurred which cannot be reversed.
If you currently have coins that have been affected by any of the problems listed above or any other problems, you can send your coins to NCS for conservation and then have the coins submitted directly to the Numismatic Guaranty Corp. (NGC) for grading. If you have any further questions about rare coin conservation, feel free to contact NCS toll free at (866) NCS COIN.