Depletion gilding was evidently used during the Chimu period (<i>ca. A.D. 1000-1470) in Peru on copper-silver-gold alloys. Analyses were made by wet chemical methods, and with the electron microbeam probe, Depletion gilding is accomplished by packing the object with a reactive powder (cementation mixture) and heating it; chlorides form from all metals except the gold, leaving the gold unattacked on the surface, This process was reproduced in the laboratory using various cementation mixtures. The difference between these alloys and tumbaga, the gold-copper alloy used in Columbia, is pointed out.