How to Remove Spray Paint From Concrete. Concrete has a porous surface and liquids like spray paint can settle in the tiny gaps, making it hard to remove. Cleaning concrete usually requires chemicals and industrial equipment. Below are some methods to remove spray paint from your concrete.
Buy a commercial paint thinner or paint removing chemical. Apply it to the dirty area and let it stand for 30 minutes. Use a hard brush to scrub the surface until the paint fades.
Rent a pressure washer from a hardware store to remove fresh spray paint. Use a washer with a power level of at least 4,000 PSI (Pounds per Square Inch). Tightly secure the rotary tube nozzle to the washer and spray high pressure water on the concrete to remove the spray paint.
Use a high-power sand blaster. Put silica or dry river sand in the appropriate compartment of the machine and water in the other compartment. Maneuver the machine over the concrete surface. A powerful sand blaster removes fresh spray paint as well as deep old stains.
Apply Methylene Chloride to the concrete with a brush and let the chemical settle into the surface. Spray water with high pressure on the area and scrub with a brush. Other effective solutions include Sodium Hydroxide, Xylene and Methyl-Ethyl-Ketone.
Prevent new stains. Coat the cleaned area with a special sealer, such as Aliphatic Urethane, to stop spray paint from seeping into the concrete surface and prevent discoloration.