How to Remove Old Rust Stains From a Concrete Driveway

Remove rust stains from a concrete driveway with oxalic acid.

Rust stains are ugly no matter where they show up. Rust is caused by water left on metal. The water corrodes the metal, forming rust. When metal objects, such as tools left on a concrete driveway, become wet, the rust transfers to the concrete. Oxalic acid bleach eats at rust without damaging the concrete, making it an effective tool in eradicating rust stains.

Things You'll Need

• Tarps or plastic coverings
• Water
• Bucket
• Mop or large sponge
• Scrub brush or stiff-bristled broom
• Garden hose
• Dish detergent

Instructions

1. Place tarps or plastic coverings on areas near the driveway where water run off occurs. Oxalic acid bleach kills vegetation it comes in contact with.

2. Mix 1 lb. of oxalic acid bleach with 1 gallon of water in a bucket. Dip a mop or large sponge into the bucket and wipe the bleach solution onto the rust stains on the concrete driveway. Allow the bleach to remain on the stains for two to three hours or however long the oxalic acid container indicates. This gives the oxalic acid time to loosen the rust from the concrete.

3. Brush the rust areas with a stiff-bristled brush or broom. Rinse the rust and oxalic acid away with a garden hose. If rust stains remain, apply the oxalic acid a second time.

4. Wet the concrete driveway with the garden hose and drop two to three drops of dish detergent onto the driveway. Scrub the driveway with a broom, then rinse soap away with the garden hose.

Tips & Warnings

• Purchase oxalic acid bleach at hardware or lawn and garden stores.

• Put on eye goggles and rubber gloves to keep oxalic acid bleach from splashing into eyes or onto your skin.

References

• Ask Tool Talk: Rust Removal or Remove Rust From Concrete
• Ask The Builder: Rust Removal From Concrete Pavers