Any conservation and/or restoration treatment of leather objects involving chemicals must follow an intensive investigation of the skin type, tanning agent, biological deterioration, etc. of the leather. Often decorative objects of leather are composed of wood, metal, and/or paper and the interaction of these materials must be considered when selecting a treatment. The author discusses the historical techniques of leather decoration in detail and describes methods and materials for relaxing, unfolding, and cleaning leather. See also AATA 20-2331.