Things You'll Need
Lemon juice or white vinegar
1 tbsp. oxalic acid crystals
1 cup warm water
Nylon scrub brush
Ladder (for reaching higher rust stains)
Popular for its longevity and low cost, vinyl siding also doesn't require much care. Rust stains inevitably occur, however, especially when air conditioning units or certain types of drainage pipes are installed against the siding. Acid-based solutions are the commonly preferred method for reversing the effects of oxidation, which causes the rust stains.
Spray the rust stains with a steady stream of water from a garden hose.
Mix a solution of 1 tbsp. oxalic acid crystals with 1 cup warm water.
Scrub the rust stained area with a nylon brush dipped in the solution.
Rinse scrubbed area with garden hose and blot dry with a clean rag.
Wear rubber gloves and protective eye gear when applying solutions.