The conservation of non-metallic seals is an aspect of archival conservation which is all too often negleted. The authors show the most usual causes and forms of damage together with various methods of treatment. Among the aspects discussed are composition and manufacture; cleaning and repair of single and double-faced seals made of beeswax, shellac and other thermoplastic compounds; the conservation and repair of papered seals; together with seals and wafers applied en placard to documents; and methods of packing and storage used in the University of Glasgow Archives.