Because of the porous nature of concrete, the best way to remove stains is by absorbing the stain from the concrete material using trisodium phosphate for oil and grease or paint stripper for paint. Rust stains can also be removed, but requires that the surface layer of concrete be dissolved.Continue Reading
For oil and grease stains, mix 1 ounce of trisodium phosphate with a cup of water and enough absorbent material to create a thick paste. Absorbent material includes baby powder, talc and diatomaceous earth, Spread the paste over the stain, and allow the mixture to draw the oil or grease from the concrete, absorbing it into the absorbent material used in the paste. After the paste dries, sweep it up from the concrete, and then clear away any remaining debris using a nylon brush.
Remove paint stains using the same process as oil and grease stains, substituting paint stripper for the trisodium phosphate and water mixture. Use a layer of stripper paste 1/4-inch to 1/2-inch thick, and wait about 20 minutes for the paste to loosen the paint. Scrape away the stripper, and wait for it to dry before disposing of it.
Rust is removed using muriatic acid. Add 1/2-cup of the acid to 2 cups of water in a large shallow plastic pan. Apply the acid to the concrete, and wait for it to stop bubbling. Scrub the area with a large handle nylon brush to remove the rust. Rinse after removal with lots of water to dilute any remaining acid. During all three removal processes, wear protective clothing and vent the room by opening any available doors and windows.Learn more about Stain Removal