Wash and dry the affected area
Wear gloves, eye protection, and a mask
Sand the rusted area with coarse sandpaper or a wire brush
Remove all loose paint and rust until clean metal is exposed
Apply a rust remover or rust converter if needed
Wipe the area clean with a degreaser or solvent
Apply body filler if there are pits or small holes
Sand the repaired area smooth
Apply a rust-inhibiting primer
Paint the area with matching automotive paint
Apply clear coat if needed
Seal the underside and hidden areas with rust protection
Check for leaks or trapped moisture and fix them
Inspect the car regularly for new rust spots