Transparent glazes on metal have been part of artistic surface treatments for at least over 1000 years. The technical development is studied from recipes dating from the 9th to the 20th century. Detailed descriptions of working methods and examples of application in paintingand architecture from the 12th century to today are given. Problems arising during conservation are illustrated with two examples: the reddish brown glaze on the cast pewter sarcophagi in the Viennese Capuchin Tomb baroque and rococo and the glazes on polychrome sculptures of the rococo. -- AATA