Depletion gilding

Depletion gilding is a method for producing a layer of nearly pure gold on an object made of gold alloy by removing the other metals from its surface. It is sometimes referred to as a 'surface enrichment' process. Depletion gilding is a method for producing a layer of nearly pure gold on an object made of gold alloy by removing the other metals from its surface. It is sometimes referred to as a 'surface enrichment' process. Most gilding methods are additive: they deposit gold that was not there before onto the surface of an object. By contrast, depletion gilding is a subtractive process whereby material is removed to increase the purity of gold that is already present on an object's surface.