A fast-acting penetrant with capillary action to penetrate deep into crevices, threads and seams to break the rust bonds that hold stuck parts together. WD-40 works on contact to free rusted nuts, bolts, threads, locks, and chains leaving behind a protective layer that prevents rust and corrosion from re-forming. It is safe to use on metal, rubber and plastic parts. Due to the lubricants in its composition, WD40 does not allow water to penetrate and remain on surfaces and mechanical parts.