Excavated bronzes present fascinating and complicated problems for their preservation, the treatment of which not only rests on technical processes, but is also influenced by aesthetics and personal taste. The general approaches to the techniques and materials for their conservation have not varied greatly during the last fifteen or twenty years, and are quite standard in the field. The Conservation Department of the Asian Art Museum of San Francisco has investigated and applied the small variety of preservative treatments over the years and has been influenced by those changes in concept which have developed. This paper presents the chronology of this museum's approaches to bronze preservation over a twenty year period, and concludes that the continual provision of proper environment is the best method to arrest corrosion, reduce alteration of the object, and retain the greatest amount of desired patina-tion. See also AATA 19-155.