Abstract: It is desired to enhance the ability of hydrogen peroxide and persalts at wash temperatures of around 30.degree. to 70.degree. C., in order to use less energy and to minimize damage to various fabric finishes. It has been proposed in the past to use transition metal compounds, including cobaltous compounds for this purpose, but the literature is self-conflicting in the way to do this. In repeat trials the simple cobaltous salts did not show much activation.The invention provides a class of activators for persalts and hydrogen peroxide comprising cobalt III ammine complexes, preferably containing 4 or 5 ammine ligands obeying the formula:Co[(NH.sub.3).sub.n M.sub.m B.sub.b T.sub.t Q.sub.q ] Y.sub.yPreferred complexes contain a chloride, bromide, hydroxyl or water ligand.Such complexes can activate particularly well at above about pH10.2, which can vary from complex to complex, and retain activity in the presence of normal concentrations of many heavy duty washing compositions.