Clean the surface of rust, grease, oil and other substances, using soap and water. You can substitute household cleaner or trisodium phosphate (TSP) if you wish, but Rust-Oleum advises against cleaning with solvents, noting that they smear grease and grime around.
Chip off rust and loose paint with the paint scraper, wire brush and sandpaper. Lightly sand glossy surfaces.
Rinse the surface with water and let it dry thoroughly.
Shake the spray can vigorously. Do this for one minute after you hear the mixing ball begin rattling.
Shake frequently while applying the primer.
Spray steadily back and forth, holding the can 10 to 16 inches from the surface, keeping the can in motion and slightly overlapping your strokes.
Apply two coats a few minutes apart. Let the primer dry thoroughly before applying a top coat.