Previous tests on metals in HC₂H₃O₂ vapour from undried wood (See <i>IIC Abstracts, 2010, Rance and Cole, Corrosion of metals by vapours from organic materials , London, 1958, p. 16) were extended to other metals and wider ranges of acidity and humidity. A very low concentration of HC₂H₃O₂ (lte 0. 5 p. p.m.) in air promoted corrosion at >70% relative humidity. Most common metals, including steel, Mg, Zn, and Cu, were affected, but A1 was relatively resistant and Sn was highly resistant. Two types of corrosion product, (i) powdery and relatively acetate-free and (ii) a deliquescent normal-acetate layer, were noted, either or both of which occurred on Cd, Mg, and Zn, according to the test condition. On steel, only (i) was formed, while (ii) was normal on Cu, brass, and Ni. Results with Sn-Cd coatings on steel and with solution-rotproofed wood are also given. -- AATA