- 1). Pour 1/2 cup dishwashing liquid into a gallon bucket. Fill the remainder of the bucket with cool water.
- 2). Wash the rust-stained area with the dishwashing liquid. Use a soft- to medium-bristled scrub brush (depending on surface type) to thoroughly clean the area. Rinse the dishwashing liquid thoroughly with cool water.
- 3). Pour one pound of oxalic acid into a gallon bucket. Fill the remainder of the bucket with cool water.
- 4). Apply the oxalic acid to the rust stain. If the rust stain is on concrete, use a mop. If the rust stain is on another surface, use a sponge to apply the oxalic acid to the stain.
- 5). Scrub the stain with a soft- to medium-bristled brush (depending on surface type) to lift the stain. Rinse the area thoroughly with cool water.
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