I painted a gearbox yonks ago....

.... all I done was, wipe off the muck and oil, get a wire brush attachment in a drill and go at it.....


... then wipe the whole thing down with a degreaser, and just sprayed on some silver-metallic paint out of a spray can.


It lasted about 12 months before all the crap turned the shiney silver, into how it almost looked before I started....

... but I guess I shouldve cleaned it atleast once in a year