This technical information sheet discusses characteristics, causes and treatment of whitening of dried wood finishes such as natural resins, shellac, drying oils, oriental lacquer, thermoplastics, beeswax, carnauba. Blanching is distinct from blush and bloom. Whitening occurs upon contact of deteriorated finishes with excessive moisture (water), diffusely reflecting visible light. Moisture may penetrate minute cracks and fissures, staining and damaging underlaying wood. Successful reversibility depends upon the nature, type, condition, thickness and reactivity of the finish, exposure time, and knowledge of finishes and their solvents. A traditional home remedy uses cooking oil or mayonnaise with cigar or cigarette ashes. Conservation treatment of an 1850 (circa) rosewood melodeon using 10% white shellac in denatured alcohol is described. Refinishing is best left to a professional conservator. Retain the original finish wherever possible to preserve the object's historical integrity. References date from 1980-1984. This is a reference for water-damaged museum artifacts, and the conservation of furniture and wooden objects. -- CCI