The corrosion products found on lead and tin objects both immediately after excavation and after storage are discussed. The lead corrosion products found on objects consist mostly of lead (2+) species, whereas the tin products consist mostly of tin (4+) species. Corrosion mechanisms are discussed. The author states that the corrosion of metals is an electro-chemical process with the anodic reaction, metal dissolution, and the cathodic reaction, oxygen reduction or hydrogen evolution, occurring at separate sites on the metal surface. The standard electrode potentials of lead and tin for the M2+/M system are given as -0.126v for lead and -0.136v for tin. The equilibrium potential-pH and Pourbaix diagrams for the lead-water system are given in the paper. The most common corrosion products found on lead objects are lead carbonate and basic lead carbonate, whose formation depends on the amount of carbon dioxide present within the system. The reaction of lead corrosion products, found on objects, to acetic acid vapors is discussed. The acetic acid will react rapidly and dissolve some of the carbonate corrosion products on the surface of the lead object, thus neutralizing the acid but leaving acetate ions. The acetate ions can then carry the electrical current of the corrosion cells and allow for the dissolution lead metal and the migration of the lead (2+) ions. The ionic species migrates away from the surface to regions where the pH and carbonate ion concentrations are higher and is then precipitated as hydrocerussite. The overall reaction is no different from one occurring in the absence of acetate, but now the basic lead carbonate forms away from the metal surface and therefore does not restrict corrosion.