Unknown quantities of varying materials are being commercially used as oil adsorptives by service stations, garages, and factories. Private interests, in order to secure part of this expanding market, considered the operation of 3 mining properties. Analyses of mine-runs were compared to analyses of 3 samples of oil adsorptive now being commercially sold. Commercial samples were primarily pumice, pumicite, and mixtures of calcite and gypsum. Mine-run samples were primarily pumice, secondary pumice, and lime. A quantitative method of measuring the efficiency of the different materials, as oil adsorptives, was used. The adsorptive efficiency of all commercial materials tested could be improved by additional sizing.