This article, like others in the Conservation Notes series, is written for non-conservation trained museum professionals such as curators and collections managers to instruct them in the theory and care of specific object materials. The article covers the nature and properties, deterioration processes, and care and treatment considerations important to semi-tanned skin objects. Semi-tanned refers to the use of brains or oils in the process of preventing putrefaction in a skin material. A table is provided which lists handling and treatment procedures while commenting on dangers and problems with the treatments. Details of storage procedures are referred back to <i>Conservation Notes</i> No. 17. -- AATA