Most coatings generally increase a tool's hardness and/or lubricity. The property of reducing friction is known as lubricity. The hydrotreatment of diesel fuel to remove sulphur also removes the compounds that provide lubricity. Others manufacture blades that are polymer-coated to enhance lubricity during a cut. The long aliphatic chains then line up towards the outside of the fiber, imparting lubricity. Lubricity of fuel plays an important role in wear that occurs in an engine. Castor oil is used because it has good lubricity and high pressure properties. Some retain their lubricity to very high temperatures. "Racing" oil or castor-based does offer excellent lubricity - at the expense of premature coking. The lubricity of many solids is attributable to a lamellar structure. The lubricity of a substance is not a material property, and cannot be measured directly. The decision on which to use has to do with lubricity and release.