How to Safely Remove Oil Stains from Garage Concrete

Concrete is a porous material, which makes it an unfortunate sponge for automotive fluids. When oil spills in your garage, it doesn't just sit on the surface; it wicks deep into the capillaries of the slab, creating a dark, persistent blemish that can attract dirt and degrade the surface over time. Ignoring a spill today often results in a permanent stain that requires heavy-duty chemical intervention later. Successfully removing an oil stain requires patience and the right chemistry. You are looking to emulsify the oil so it can be lifted out of the pores and washed away. Done well, the concrete will return to its natural light grey state, preventing the oil from re-emerging or tracking into your home. Follow this process to strip the stain cleanly without damaging the integrity of your floor.

1. Soak Up the Spill First. Pour a generous amount of unscented clay-based cat litter over the fresh spill. Use your boot to grind the litter into the oil and let it sit for at least 24 hours to wick the liquid up.
2. Clear Away the Litter. Sweep up the saturated litter with a stiff broom and dispose of it in a sealed bag. Ensure no loose granules remain on the concrete surface.
3. Saturate With Degreaser. Saturate the remaining stain with a concentrated heavy-duty concrete degreaser or a paste made of water and TSP. Apply it liberally so the entire area is covered.
4. Scrub With Real Pressure. Use a stiff-bristle nylon brush to scrub the degreaser into the concrete in a circular motion. Apply firm downward pressure to reach deep into the pores.
5. Blast Away Residue. Use a garden hose with a high-pressure nozzle to blast the emulsified oil and degreaser off the concrete. Push the soapy water toward a floor drain or the driveway apron.
6. Let It Dry, Then Inspect. Allow the area to air dry completely, which may take several hours. If a shadow of the stain remains, repeat the degreaser and scrubbing process.