Whitening. Metal preparation and cleaning of blanks prior to coining, the process removes tarnish, toning, surface debris and softens the blanks by annealing. The term is not a precise one and is not widely used in metalworking, although metal softening and cleaning is universally employed for most all metalworking. When employed at mints, the process leaves the blanks lighter color than before, hence the use of the term whitening. The process can occur either before or after upsetting.

Generally at the U.S. Mints whitening was done before upsetting in the 19th century, and after upsetting in the 20th century. Whitening was normally performed after annealing and upsetting. The bright planchets deteriorated somewhat quickly unless used within a short time.

Formerly a special room was devoted to whitening at U.S. mints (until 1969). At the present mints the process is done after upsetting in their own areas.