A frequent procedure of adding small amounts of volatile amines to steam in order to prevent boiler corrosion in steam humidification systems is noted. In experiments carried out in the Royal Ontario Museum, University of Toronto, samples of polished copper and sterling silver were exposed to leaking steam containing octadecylamine ( Superfilmine 20 ) at a concentration of 1 pound in 1 million pounds of steam. No discoloration was noted after 3 months; after a 12 month exposure, however both metals had tarnished. Samples previously coated with a brushed lacquer film ( Incralac ) remained unaffected during the tests. The author stresses that the experimental conditions were much more severe than would normally be encountered in museum galleries, and regards steam humidification as permissible, especially when protective lacquers are used.