A short history of cartonnage decoration in Egypt, c. 323BC-130AD, introduces a discussion of the techniques involved in the construction of plaster masks. The deterioration of the masks included grime, staining, old repairs, old attempts at cleaning, damage from soluble salts and from plaster used to embed mounting hooks. Conservation treatment consisted of dusting, cleaning with a gum rubber eraser, cleaning with acetone or trichloroethylene where possible, and consolidating mainly with Acryloid B-72 in xylene or toluene. Inlaid glass eyes were cleaned with acetone and 15% EDTA solution, followed by lacquering with B-72. A salt damaged mask was coated with B-72 and then swabbed with distilled water to remove the salts.