How to Get Acid Off of Concrete

Place hot water onto the acid stain to loosen up the stain. Place a dry wash cloth onto the stain, and pour boiling water onto the wash cloth. Allow the water and wash cloth to sit on the acid stain for 30 minutes. Remove the wash cloth.

Mix TSP (trisodium phosphate) and boiling water in a 5-gallon bucket. Wear rubber gloves and eye goggles before proceeding. Dip an acid brush into the bucket, and apply the mixture to the acid stain. Scrub vigorously with the acid brush, and allow the TSP to set for 10 minutes. Pour boiling water onto the TSP, and allow the stain to dry. Apply TSP to the stain, and scrub once again with an acid brush. Allow the TSP to set for five minutes.

Remove the TSP with a pressure washer. Rent the pressure washer from any tool rental store. Place a yellow tip onto the pressure washer wand, and spray slowly across the acid stain. Wear goggles to prevent TSP from splashing onto your eyes. Spray across the surface at an angle rather than directly. Because the TSP has loosened the surface of the concrete, direct pressure may damage the surface.

Scrub the surface of the concrete with a wool pad, working in circular motions. Keep the concrete wet with the pressure washer, alternating pressured water with wool pad scrubbing. Allow the concrete to dry, and reapply TSP and boiling water, scrubbing it into the concrete with a wool pad. Wear rubber gloves when scrubbing with the wool pad and TSP.