Tarnish
Varnish. Lacquer without pigments or color added. Varnishes are either solutions of resins (natural or artificial) or spirit varnishes in volatile solvents. See lacquer.
excerpted with permission from
An Encyclopedia of Coin and Medal Technology
For Artists, Makers, Collectors and Curators
COMPILED AND WRITTEN BY D. WAYNE JOHNSON
Roger W. Burdette, Editor