copper anti corrosion agents are benzotriazole bta or bis benzotriazole and substituted derivatives thereof other suitable agents are organic and or inorganic redox active substances and paraffin oil benzotriazole derivatives are those compounds in which the available substitution sites on the aromatic ring are partially or completely substituted suitable substituents are linear or branch chain c 1 20 alkyl groups and hydroxyl thio phenyl or halogen such as fluorine chlorine bromine and iodine a preferred substituted benzotriazole is tolyltriazole it is known to include a source of multivalent ions in detergent compositions and in particular in automatic dishwashing compositions for anti corrosion benefits for example multivalent ions and especially zinc bismuth and or manganese ions have been included for their ability to inhibit such corrosion organic and inorganic redox active substances which are known as suitable for use as silver copper corrosion inhibitors are mentioned in wo 94 26860 and wo 94 26859 suitable inorganic redox active substances are for example metal salts and or metal complexes chosen from the group consisting of zinc manganese titanium zirconium hafnium vanadium cobalt and cerium salts and or complexes the metals being in one of the oxidation states ii iii iv v or vi particularly suitable metal salts and or metal complexes are chosen from.