It's just like how used car salesmen use WD 40 to clean up a motor. When black parts get dry the color gets chalky looking. Oils give the surface some gloss and make it look new.
HD has a product called S100 Engine Brightener (used to be called Pig Spit). It's made to keep the black parts of the motor looking good and is based on the same principle. It's just an oil blend in an aerosol can. I use it on my bike all the time, motor and frame, works great.
HD has a product called S100 Engine Brightener (used to be called Pig Spit). It's made to keep the black parts of the motor looking good and is based on the same principle. It's just an oil blend in an aerosol can. I use it on my bike all the time, motor and frame, works great.