Painting a heater radiator with latex paint results in an unforgettable aroma when it is fired up for use. Latex paints are not designed to withstand the higher temperatures that radiators maintain. The paint will soften, release fumes and then crack when the iron radiator cools off. This paint will have to be removed and another appropriate finish product applied. Manual stripping of the paint is necessary since the use of solvents will yield the same fume problems when using the radiator.
Sand all surfaces you can reach using a drill with a wire sanding wheel attached. You can purchase a sanding wheel at most home improvement stores, and it attaches by inserting the wheel and tightening clockwise with the drill chuck. Slowly rake the wire wheel against the surface of the metal. Keep the drill in motion to avoid pitting the iron.