I've had great luck using this stuff on the inside of a boxed Jeep frame. It's a paint, not a wax or an oil. I'm not certain that the actual paint is all that special, but the 24" long nozzle is fantastic. I ended up keeping the nozzle, cleaned it out with mineral spirits, and put it on a can of Rustoleum satin black to give another coat to the inside of the frame the next day.
http://www.eastwood.com/eastwood-int...z-aerosol.html