How Do You Remove Firecracker Stains From Concrete?
Black powder and sulfur from fireworks can create stains on cement which are moderately difficult to remove. Many harsh chemical solvents can further stain and damage the concrete surface. The safest way to remove such stains is to use a combination of tools and techniques, as very seldom will just one technique work on its own. Apply a small amount of diluted bleach solution to the stain. The dilution should be three parts water to one part bleach. Immediately after applying the solution, scrub the stain vigorously for three to five minutes. Pressure wash the stain location, holding the spray nozzle within twelve inches of the stain. Be sure to flush the bleach off of the stain area within five minutes to prevent excessive whitening of the concrete. Allow to air dry in the sun for about two days. If necessary, repeat these steps one additional time.
