How to Remove Rust Stains With Oxalic Acid

Depending on the surface that is stained, rust stains can be particularly hard to remove. Concrete and other porous surfaces are more difficult to clean than sealed surfaces such as vinyl or ceramic tile, and often, the rust has gone unnoticed for a great length of time on cement surfaces such as garage flooring. Oxalic acid is often recommended as a good product for removing rust stains. Oxalic acid is mildly toxic but not as abrasive as other commercial products. Before you try a harsher chemical, try removing rust stains with oxalic acid.

Things You'll Need

• Dishwashing liquid
• Bucket
• Soft or medium-bristled brush
• Oxalic acid

Instructions

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.

Tips & Warnings

• Wear gloves and safety glasses when using the acid. Wear clothing that covers all of your skin.

References

• Ask Tool Talk: Rust Removal or Remove Rust from Concrete