- Mix one cup of trisodium phosphate (TSP) with one gallon of hot water. Pour the TSP on the oil stain, and allow it to soak for 20 to 30 minutes. Scrub thoroughly using a plastic-bristled brush and rinse with a hose. Wear protective goggles and gloves because TSP is caustic.
- Spread a layer of fresh clay kitty litter over the stained spot and leave it on for two to three days. Sweep up the kitty litter. Alternatively, sprinkle a dry concrete mix over the stained area, and leave it on for three days, and then clean it with a wet mop.
- Apply an enzymatic solution to the stained area so as to dissolve the substance causing the stain. Rinse the solution off thoroughly with a lot of water to completely remove the enzymatic solution. You should wear safety goggles and rubber gloves, because enzymatic solution is caustic.
- Remove light rust stains from your concrete floor by moping them with a solution of oxalic acid. This is typically available from your hardware or home improvement store in crystal powder form. Follow the manufacturer's directions to dilute it with water, which is usually one pound of the oxalic acid crystal powder with a gallon of water. Mop the floor with the solution and a long-handled mop. After six or more hours, scrub the floor using a stiff plastic brush, and then rinse it with clear water. It is important to wear safety goggles and rubber gloves when working with oxalic acid, which is highly caustic.
- Fresh grease and oil stains, which are quite common on garage floors, can be cleaned with mild liquid soap, such as dish soap. Wet the stained area with water, and then apply some dish soap into the stain. Using a plastic-bristled brush, work the soap into a thick lather. Blot away the excess soap with an old towel.
- Once you get rid of the stain from your concrete floor, allow the floor to dry for a few hours, and then paint it with a concrete sealant to keep it shining and free from stains. Do not use a wire-bristled brush on concrete floors. In addition to the risk of scratching the concrete surface, a wire-bristled brush may become rusty, which will stain on your floor.
