Orange Tough 90 is a natural solvent degreaser with d-limonene for extremely heavy duty degreasing and cleaning of engines, machinery tools, grills, all metals and concrete. With a blend of 90% D-limonene and 10% detergent surfactants, Orange Tough 90 is 100% active. The biodegradable formula quickly cuts through grease, oil, dirt, cosmoline, tar, rubber burns, carbon creosote, many inks and adhesives.