Metallurgical studies of a group of gilt copper objects from Loma Negra (Peru) have shown that the gilding was achieved by an electrochemical replacement plating process in which gold and silver are dissolved in an aqueous solution of corrosive minerals. The precious metals are then plated from solution onto the copper objects. Moche metal craftsmen can now be credited with having developed the two most sophisiicated Andean gilding procedures: depletion gilding and electrochemical replacement plating. Objects from Loma Negra, metal construction techniques and photomicrographs of cross sections of original and experimental gilt copper objects are illustrated. Experimental techniques used to reproduce Moche gilt surfaces are also discussed. -- AATA