NNP

Proof Polish.  A diamond dust or emery abrasive compound and the action which is accomplished with a power wheel to polish the area of a die where a proof finish is required. The abrasive  is often used in a slurry or paste form; the polishing is often followed by a polishing with rouge on the same surface of the die. This two-step polishing produces a die which imparts a mirror-like struck surface with a very high reflectiveness.

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