oversilver
/ɒvərˈsɪlvər/Definitions
1. noun
A thin layer of silver deposited on the surface of an object, especially a coin or a medal, by chemical reaction.
“The expert carefully examined the coin to determine the extent of the oversilvering.”
2. verb
To coat with a thin layer of silver, especially by chemical reaction.
“The process of oversilvering can enhance the appearance of an object.”