How to Remove Concrete Acid Stain

What You'll Need
protective gear (rubber gloves and boots, safety goggles)
handkerchief or surgical mask
garden hose near ample water supply
oxalic acid
TSP (tri-sodium phosphate)
muriatic acid
concrete sealer
stiff bristle brush or wire brush

While a concrete acid stain looks unpleasant, acid-stained concrete floors are usually a popular choice for the driveway or the patio. Some people are opting to use them as an indoor flooring option as well. This concrete floor brings out an air of old elegance to any home. Maintenance is very minimal and is highly durable in terms of the wear and tear it undergoes. In time, it also fades away and may sometimes leave an unpleasant pattern on the floor. Here are some tips to remove a concrete acid stain without seeking the help of a professional cleaner.

Step 1 - Put on Protective Gear

Remember to always wear protective gear before using any of the cleaning products above. Rubber gloves and boots will protect your hands and feet from any accidental spillage of the acid. Wearing long-sleeved shirts and pants/jeans will also protect your arms and legs. Safety goggles and a handkerchief (or a surgical mask, if you have one) will help shield your eyes and nose from the poisonous fumes.

Step 2 - Use Oxalic Acid

Start off with the oxalic acid first. Oxalic acid comes in a powder form and can be bought from the local drugstore or supermarket. Mix and dissolve the acid in either warm or hot water. Always follow the instructions on the box for various mixing strengths. Prepare the area where you need to apply the acid by saturating it with water completely and letting it dry. Dip the brush into the solution and apply it to a small area first. Do the same to another spot until you have covered the area with the solution. Let the solution sit for 15 to 20 minutes. Wash off the entire place with water using a garden hose for maximum area coverage. Repeat the procedure until the stains disappear.

Step 3 - Treat with TSP

Use TSP (tri-sodium phosphate) if the oxalic acid doesn’t do the job. It can be bought from any home improvement store or a local paint store. The same procedures apply to the oxalic acid but it always helps to refer to the instructions on the box to get the right solution.

Step 4 - Try Muriatic Acid

Treat with muriatic acid if all else fails. You can buy muriatic acid from your supermarket, but you should handle it with extreme caution. Usually a solution of 4 parts water and 1 part muriatic acid is enough for a heavy-duty cleaning unless specified otherwise. Procedures used for the oxalic acid and TSP are also applicable here.

Step 5 - Apply Concrete Sealer

Apply concrete sealer to the area with the stain finally removed. When acids are used, they tend to completely strip the concrete and make it more porous, thereby weakening its structure. The sealer will help protect the area from water seepage, foot traffic, and the natural elements.