The article describes metallurgical technologies developed by the Moche culture in South America, in which copper was plated with gold or silver (by electrochemical replacement) and alloys of copper, gold, and silver were treated to produce a gold or silver surface (by depletion gilding or silvering, especially from tumbaga alloys). These techniques, used also by the Inca and other Andean cultures, were analyzed by studying a large number of Moche-style metal objects found at Loma Negra (Peru) and then duplicating the presumed methods experimentally in the laboratory. Possible relationships between favored metallurgical techniques and cultural ideology are suggested. See also AATA 16-1722, 17-1574, and 19-690. -- AATA