This invention relates to a method of making selected oxidizers or other free radical-producing compounds become more effective chemical etchants and/or oxidizers for CMP activities by promoting the formation of the free radicals in a CMP composition with one or more activators. The activator comprises iron, copper or combinations thereof. The activator coated abrasive is particularly effective as it brings the activator in close proximity to the targeted material on the substrate surface, and thus facilitates or accelerates the removal reaction substantially at the site of the targeted material. The activator reacts with the per-type oxidizer to form at least one oxygen-containing free radical. The invention further provides a method that employs the composition in the polishing of a feature or layer, such as a metal film, on a substrate surface. The invention additionally provides a substrate produced by this method.