How do I Clean Black Walnut Stains From Concrete?
- 1). Pour a small amount of bleach, such as Clorox Outdoor Bleach, on a small area of stain. Scrub vigorously with a long-handled nylon brush.
- 2). Rinse thoroughly and allow to dry. If stain is removed, repeat on entire stained area. If not, proceed to the next step.
- 3). Purchase or rent a power washer from a home improvement store. Add bleach to the power washer according to the manufacturer's directions and wash the stain. Do not use pressure above 2500 psi on concrete. Allow to dry thoroughly. If stain is still not removed move to next step.
- 4). Pour one part muriatic acid into nine parts water. Use extreme caution. Muriatic acid is extremely toxic and corrosive and can be deadly to animals. Protect surrounding siding, doors or other features adjoining the concrete.
- 5). Saturate the area to be cleaned with water.
- 6). Apply the muriatic acid solution with a plastic watering can. Distribute the solution with a scrub brush and allow to sit for five to 10 minutes. Rinse several times with large amounts of water.
- 7). Check the concrete with a pH test strip. Continue rinsing until the test strip indicates a pH of 7 or higher.
- 8). Neutralize remaining muriatic acid by mixing three to four cups of baking soda or lime in a gallon of water. Slowly add muriatic acid. Stir carefully until the fizzing stops. You can safely dispose of the solution after this process is complete.
