How to Clean Oil Stains from a Garage Floor — Toronto Home Guide

Oil stains on concrete garage floors are common and become more difficult to remove the longer they sit. Fresh spills should be treated immediately; older stains require a degreaser and some scrubbing effort.

Fresh Oil Spills

1. Cover the spill immediately with an absorbent material — cat litter, sawdust, baking soda, or commercial oil absorbent
2. Let it sit for at least 30 minutes (overnight for large spills)
3. Sweep up the absorbent material
4. Apply dish soap or a degreaser directly to the remaining stain
5. Scrub with a stiff-bristle brush
6. Rinse with hot water

Set-In Oil Stains

1. Pour a commercial degreaser (such as Simple Green, Purple Power, or a dedicated concrete degreaser) directly onto the stain
2. Let it penetrate for 10–15 minutes
3. Scrub vigorously with a stiff-bristle brush or push broom
4. Rinse with a garden hose or pressure washer
5. Repeat if needed — old stains often require 2–3 treatments

Heavy Staining

For stains that have soaked deep into the concrete over years:

• Apply a poultice of powdered laundry detergent and water (paste consistency) over the stain
• Cover with plastic sheeting and tape the edges to slow drying
• Leave for 24 hours — the poultice draws the oil out of the concrete as it dries
• Scrape up and rinse

Tips

• A pressure washer makes rinsing significantly more effective than a garden hose for garage floor cleaning
• Applying a concrete sealer after cleaning prevents future stains from penetrating as deeply
• Use an oil drip pan under vehicles that leak — prevention is far easier than cleaning