Rust Remover Spray

WD-40 is the trademark name of a penetrating oil and water-displacing spray. It was developed in 1953 by Norm Larsen, founder of the Rocket Chemical Company, in San Diego, California. WD-40, abbreviated from the phrase "Water Displacement, 40th formula," was originally designed to repel water and prevent corrosion, and later was found to have numerous household uses.

WD-40 was first used by Convair to protect the outer skin, and more importantly, the paper thin "balloon tanks" of the Atlas missile from rust and corrosion.[2][3] These stainless steel fuel tanks were so thin that, when empty, they had to be kept inflated with nitrogen gas to prevent their collapse.
WD-40 first became commercially available on store shelves in San Diego in 1958.
Function
The long-term active ingredient is a non-volatile, viscous oil which remains on the surface, providing lubrication and protection from moisture.[4] This is diluted with a volatile hydrocarbon to give a low viscosity fluid which can be sprayed and thus penetrate crevices. The volatile hydrocarbon then evaporates, leaving the oil behind. A propellant (originally a low-molecular weight hydrocarbon, now carbon dioxide) provides gas pressure in the can to force the liquid through the spray nozzle, then evaporates away.