During conservation the documentary qualities of the object must be respected. The surface is the most representative part of a stone object. Sculptures in the open air, and parts of buildings which are in bad condition may be replaced with copies, while the original is put into a museum. Methods of conservation include: fixing, filling in, impregnating, removing of crusts, and evening up. There is no method to deal effectively with blisters of deformed surface crust. See also 16-194. -- AATA