The theory of conservation is discussed for the metals most commonly found in ship wrecks, tin and pewter, iron, copper and copper alloys, silver, lead, gold, aluminium and composite artifacts. Details are given on treatment methods and some points to assist in treatment choice are covered. Subjects covered include: removal of concretions from artifacts; iron deterioration, stabilization theory and practical treatments; copper artifact; chemical stripping, chloride removal; benzotriazole treatment and electrons. A discussion of the use of x-radiography and description of methods of chloride analysis are also given.