A scratch is a type of mechanical damage that has moved or removed metal from the surface of a coin
By Numismatic Conservation Services (NCS) ……
It is said that it is better to prevent a problem rather than correct it once it has occurred. In much of our numismatic pursuits this adage is true. Environmental damage and PVC residues can often be corrected after they have begun, but other issues do not have such promising outcomes. Scratches are one of the afflictions that are not only irreversible, but also occur too quickly to mitigate.
A scratch is a type of mechanical damage that has moved or removed metal from the surface of a coin. Any attempt to cover a scratch will cause additional moving and removing of the surface metal, which results in additional damage. NCS therefore does not attempt to repair mechanical damage such as scratches or holes.
There are myriad ways that scratches occur. Many coins are scratched long before that coin becomes part of someone’s coin collection. Normal circulation can cause wear and, sometimes, surface damage such as scratches.
Scratches that occur while a coin is in a numismatist’s possession may be due to improper cleaning methods or an accident. In addition, a poor choice of coin holder can lead to a coin being scratched.
A few popular types of coin holders can leave a coin open to potential damage. Among these are the commonly used cardboard fold-over holders with a clear Mylar plastic window in the center to view the coin. These are often called “two by twos” by numismatists because they are usually 2 inches by 2 inches in size. Samples are used to seal this type of holder. Unfortunately, the staple ends may puncture the Mylar window and scratch the surface of a neighboring coin, or the coin may be scratched upon removal from one of these holders. To help prevent this damage from occurring, make sure to carefully compress the round ends of the staple with small pliers so they are flush with the cardboard. A staple that is flush with the cardboard will be less likely to inadvertently harm a neighboring coin. When removing a coin from a cardboard two by two, carefully remove the staple before attempting to remove the coin.
An extreme version of a coin with scratches. A sharp object was clearly in contact with the surface of this modern 2010 Gold Eagle $50. Left: Before conservation; Right: After conservation. Images courtesy NCS
Scratches can sometimes be hidden or partially hidden by residues and undesirable toning. While NCS conservation can safely remove these surface contaminants, it cannot remove any underlying mechanical damage such as scratches. Nothing NCS does will cause scratches to occur, but NCS cannot do anything to remove scratches.