Blanch, Blanching. A process of improving the appearance of a metal surface, as a blank, often for the removal of dark toning; a form of metal cleaning. A typical blanching process consists of dipping in acid, washing in water and drying in hot sawdust; there are many blanching methods. Other methods of metal cleaning can remove other forms of tarnish and corrosion. The process was also called whitening, or brightening and some mints had whitening or blanching rooms or departments where this was done.

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C66 {1988} Cooper p 107, 239-40.