Abstract: A vitreous bonded abrasive article, more particularly a grinding wheel, having improved grinding performance is provided wherein the open pores of the abrasive article contain an impregnant which comprises at least one water insoluble, sulfur bearing organic substance having at least one carbon to sulfur bond, at least about 5% by weight sulfur and a melting point of at least about 30° C. said melting point being at least 10° C. below the decomposition temperature of the substance and selected from the group consisting of substituted and unsubstituted aliphatic, aromatic, cycloaliphatic, alkenyl, alkynyl, alkylaryl, arylalkyl and substituted heterocyclic sulfur bearing organic substances or a mixture of said substances grinding aid. The impregnant is free of a medium, other than the water insoluble, sulfur bearing substance, in which the substance or a mixture of such substances is dissolved or dispersed.