Cosmoline is the genericized trademark for a common class of brown, wax-like petroleum-based corrosion inhibitors, typically conforming to United States Military Standard MIL-C-11796C Class 3. They are viscous when freshly applied, have a slight fluorescence, and solidify over time with exposure to air. The main ingredient in cosmoline is aliphatic petroleum solvent, which is volatile and evaporates over time. Description Cosmoline was developed by Houghton International in the 1860s or 1870s as a pharmaceutical product. The original Cosmoline was an ointment and was used for many different cosmetic and medical purposes, it was even advocated to promote hair growth. It was kept in homes to disinfect wounds and was used by veterinarians to treat cuts, abrasions, bruises and sprains. Cosmoline could even be found on farms, where it was used to relieve swelling in cow's udders. Cosmoline became widely known when it received a government specification as a rust preventive and began its use by the military to protect various equipment from rust and corrosion. Cosmoline could be found on military equipment in the Spanish–American War, World War I, World War II, and the Korean and Vietnam Wars. Cosmoline conforms to MIL-SPEC (MIL-C-11796C, Class 3) for Preservative and Sealing Compounds. Chemically, Cosmoline is a homogeneous mixture of oily and waxy long-chain, non-polar hydrocarbons. It is always brown in color, but can differ in viscosity and shear strength. Cosmoline melts at 113–125 °F (45–52 °C) and has a flash point of 365 °F (185 °C). Use The most common use of Cosmoline is in the storage and preservation of some firearms, hand tools, machine tools and their tooling, and marine equipment. Entire vehicles can be preserved with cosmoline, as was attempted with Miss Belvedere. Cosmoline is also frequently applied to automotive disc brake rotors at the factory, to prevent corrosion inside the box before the rotor is placed into service on a vehicle. It is easily removed by spraying brake cleaner on the braking surfaces of the rotor although brake pad manufacturers do not recommend this technique. These manufacturers recommend that rotors be washed with dish soap and water to remove cosmoline, as well as after machining brake drums and rotors. During World War II cosmoline was used to coat weapons, including entire tanks, for long sea voyages, to prevent corrosion in salty maritime conditions. U.S. Coast Artillerymen serving the huge coastal artillery batteries were known as "Cosmoliners" as they were