How Do I Remove Rust from a Concrete Floor?
- 1). Spray a cleaner that contains oxalic acid directly onto the rust stain. Many cleaners contain oxalic acid and are widely available at home improvement stores. A few oxalic acid stain lifters are sold in powder form. Add water to the powder to make a paste. Scrub the stain with a stiff bristle brush. Allow the oxalic acid to remain on the stain surface for five minutes and then rinse away. If the stain still remains, then reapply.
- 2). Apply trisodium phosphate powder to tough stains that are not removed by oxalic acid. Trisodium phosphate powder is widely available to home improvement stores. Mix 1/2 cup of trisodium phosphate with a 1/2 gallon of hot or boiling water. Pour over the stain and allow the solution to sit for 20 minutes. Scrub with a stiff bristle brush and then rinse with warm water. If the stain persists, reapply the solution.
- 3). Apply 1 cup of muriatic acid mixed with 4 cups of hot water directly to the rust stain. Only use muriatic acid to treat very stubborn rust stains. The muriatic acid will eat away the top layer of the concrete and successfully remove the surface stain. Rinse the solution away with hot water. Reseal the area of the concrete using a clear concrete sealer. Muriatic acid and clear concrete sealer are both available at home improvement stores. Muriatic acid is also sold at pool supply stores.