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Cosmoline is the genericized trademark
Genericized trademark
A genericized trademark is a trademark or brand name that has become the colloquial or generic description for, or synonymous with, a general class of product or service, rather than as an indicator of source or affiliation as intended by the trademark's holder...

 for a generic class of rust preventatives, typically conforming to MIL-C-11796C Class 3, that are a brown colored wax
thumb|right|[[Cetyl palmitate]], a typical wax ester.Wax refers to a class of chemical compounds that are plastic near ambient temperatures. Characteristically, they melt above 45 °C to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, nonpolar solvents...

-like mass; have a slight fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation...

; and have a petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...

-like odor
An odor or odour is caused by one or more volatilized chemical compounds, generally at a very low concentration, that humans or other animals perceive by the sense of olfaction. Odors are also commonly called scents, which can refer to both pleasant and unpleasant odors...

 and taste (as detected when working with it).

Chemically, cosmoline is a homogeneous mixture of oily and waxy long-chain, non-polar hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....

s. It is always brown in color, but can differ in viscosity
Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...

 and shear strength
Shear strength
Shear strength in engineering is a term used to describe the strength of a material or component against the type of yield or structural failure where the material or component fails in shear. A shear load is a force that tends to produce a sliding failure on a material along a plane that is...

. Cosmoline melts at 113-125 °F (45–52 °C) and has a flash point
Flash point
The flash point of a volatile material is the lowest temperature at which it can vaporize to form an ignitable mixture in air. Measuring a flash point requires an ignition source...

 of 365 °F (185 °C).

Its most common use is in the storage and preservation of some firearm
A firearm is a weapon that launches one, or many, projectile at high velocity through confined burning of a propellant. This subsonic burning process is technically known as deflagration, as opposed to supersonic combustion known as a detonation. In older firearms, the propellant was typically...

s, hand tools, machine tools and their tooling, and marine equipment. Entire vehicles can be preserved with cosmoline. Notable Egyptologist Dr. Zahi Hawass
Zahi Hawass
Zahi Hawass is an Egyptian archaeologist, an Egyptologist, and former Minister of State for Antiquities Affairs. He has also worked at archaeological sites in the Nile Delta, the Western Desert, and the Upper Nile Valley....

 recently disclosed that ancient Egyptian mummification practices from the third to fifth dynasties utilized a chemical compound molecularly similar to cosmoline.

During World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, U.S. Coast Artillerymen (serving the huge coastal artillery
Coastal artillery
Coastal artillery is the branch of armed forces concerned with operating anti-ship artillery or fixed gun batteries in coastal fortifications....

 batteries) were known as "Cosmoliners" because they were tasked with the near constant cosmoline application ("greasing down") of the guns.

During Pacific island campaigns in World War II, the United States Marines sang a song about cosmoline. Adapting the popular big-band tune "Tangerine," they would sing "Cosmoline...keeps my rifle clean."

Due to its gelatinous nature, cosmoline can be difficult to remove completely from firearms and, as such, is being extensively replaced with vacuum-pack PET film
PET film (biaxially oriented)
BoPET is a polyester film made from stretched polyethylene terephthalate and is used for its high tensile strength, chemical and dimensional stability, transparency, reflectivity, gas and aroma barrier properties and electrical insulation.A variety of companies manufacture boPET and other...


Aging, solidification, removal

Cosmoline that is fairly fresh, or that has been hermetically
Hermetic seal
A hermetic seal is the quality of being airtight. In common usage, the term often implies being impervious to air or gas. When used technically, it is stated in conjunction with a specific test method and conditions of usage.-Etymology :...

 sealed in a plastic bag or shrinkwrap, remains a grease
Grease may refer to:* Grease , a type of industrial lubricant* Yellow grease, in rendering, used frying oils, or lower-quality grades of tallow...

-like viscous fluid, and mostly wipes off with a rag, leaving only a thin film behind. Cosmoline that is older and has had air exposure usually solidifies after a few years, as the volatile
Volatility (chemistry)
In chemistry and physics, volatility is the tendency of a substance to vaporize. Volatility is directly related to a substance's vapor pressure. At a given temperature, a substance with higher vapor pressure vaporizes more readily than a substance with a lower vapor pressure.The term is primarily...

 hydrocarbon fraction evaporates and leaves behind only the waxy hydrocarbon fraction. The solid wax does not readily wipe off. It can be scraped off, although the scraping is laborious and leaves crumbs to be swept or vacuumed away. A useful method of cleaning a tool of crusted cosmoline is to allow a penetrating oil (such as WD-40
WD-40 is the trademark name of a United States-made water-displacing spray. It was developed in 1953 by Norm Larsen, founder of the Rocket Chemical Company, San Diego, California. It was originally designed to repel water and prevent corrosion, and later was found to have numerous household...

, CRC 5-56
CRC Industries
CRC Industries is a manufacturer and distributor of industrial chemicals for maintenance and repair of marine, electrical, industrial, automotive and aviation equipment....

, or equivalent) to soak into it for several minutes or hours, which typically restores it to a viscous-fluid state, allowing it to be wiped off. An additional method of cosmoline removal on new parts is to use a closed cabinet parts washer that utilizes the power wash process. Removal of cosmoline with an aqueous parts washer
Parts washer
A parts washer is a piece of equipment used to remove contaminants or debris, such as dirt, grime, carbon, oil, grease, metal chips, cutting fluids, mold release agents, ink, paint, and corrosion from workpieces...

requires high heat, the proper aqueous detergent and the correct hydraulic impact pressure.

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