Read more about a recently conserved coin from the NCS conservation laboratory.
Coin holders containing the plasticizer PVC can with time and common environmental conditions lead to the development of dangerous residues on the surface of the coin within. Such is the case with this 1916-S Buffalo Nickel recently submitted to NCS. The green wet appearing residues in the crevices of the devices and legends are a clear sign that this coin has spent too much time in a holder containing PVC.
If left alone, PVC residue can permanently damage the surface of a coin through corrosion. This buffalo nickel was submitted for conservation just in time as the residue was able to be safely removed. A lustrous natural appearing coin was left after the green residue was removed. The coin was able to grade numerically with NGC following the conservation work.