Function The long-term active ingredient is a non-volatile viscous oil which remains on the surface to which it is applied, giving lubrication and protection from moisture. This oil is diluted with a volatile hydrocarbon to make a low viscosity fluid which can be aerosolized to penetrate crevices. The volatile hydrocarbon then evaporates, leaving behind the oil. A propellant (originally a low-molecular-weight hydrocarbon, now carbon dioxide) creates pressure in the can to force the liquid through the can's nozzle before evaporating. Its properties make it useful in both domestic and commercial settings. Typical uses for WD-40 include removing dirt and extricating jammed screws and bolts. It can also be used to loosen stubborn zippers and displace moisture. Due to its low viscosity, WD-40 is not always a suitable oil for certain tasks. Applications that require higher viscosity oils may use motor oils. Those requiring a mid-range oil could use honing oil.