MIL-PRF-87937 TYPE II is a water-based, non-toxic, biodegradable, cleaning solution for use on metal and other hard surfaces.
It is used to remove hydrocarbon and other organic residue as well as inorganic material from surfaces and is non-corrosive to a wide array of metals, plastics, rubber and other materials.
It is also used to clean outer surfaces of aircraft and bare metal prior to painting among many other general uses. Etc.
Both Military and Domestic Airlines headquartered use MIL-PRF-87937 TYPE II to wash the exteriors of aircraft.