Oil Stains on Garage Floor

July 27, 2011 8:13 AM

How can I best remove old oil stains from my concrete garage floor?

My old car leaked oil and I was lazy about cleaning it up. It's been a while and I want to clean it up, and I have no idea how.

Anybody done this before? What's the best way to go about it? I'd like to finish the garage floor and I need to get this giant stained area good and cleaned up before I do that.

posted by PFL to home & garden (9 answers total)

Kitty litter.. Click/clack routinely say the same, and their forum chimes in too..
posted by k5.user at 8:22 AM on July 27, 2011

I can't find the link where I learned this trick, but it was from some concrete industry association or something. Anyhow, their method was this: Mix up a thick paste of water and agricultural lime (from the hardware store or garden center), spread it over the stained area and scrub it in with a wire brush. Allow to dry thoroughly, which may take several days. The lime will absorb the oil as it dries out. Brush loose and sweep away. Repeat as necessary.

I used this method to remove a stain where a container of waste motor oil leaked on my concrete patio, and it worked very well.
posted by jon1270 at 8:24 AM on July 27, 2011

Soak up any remaining surface oil with kitty litter. Apply degreaser (a strong one - get it in bulk from the sort of auto shop that caters to mechanics). Let it sit for a few minutes. Hit the stained area with a high pressure hose (one with a compressor behind it). The oil will have soaked in and you won't get it all out, but you can knock off the top layer and probably a bit of concrete with it. Repeat as many times as you can bear. Then paint.
posted by Ahab at 8:25 AM on July 27, 2011

Reader's Digest has a few other solutions, including ammonia, baking soda, Kool-aid, oven cleaner, cat litter + soda-pop, and WD-40.
posted by filthy light thief at 8:54 AM on July 27, 2011

My brother-in-law does concrete finishing and he is a big fan of the water and lime trick.
posted by xedrik at 9:08 AM on July 27, 2011

Liquid laundry detergent and a brush can help. Hose off when done.
posted by procrastination at 11:00 AM on July 27, 2011

I've reduced (but not eliminated) these stains by spraying oven cleaner onto the affected area, followed by later rinsing it off by first pouring boiling water onto the surface and then sweeping it away. Worked well enough to get my landlady off my ass.
posted by Rash at 12:03 PM on July 27, 2011

I cleaned some sort of grease/oil stain from asphalt using a store-brand Pine-Sol (one marked "biodegradeable" because this drained to a storm sewer) diluted in water at the extra-strength recipe. Apply, scrub in with a push broom, soak for half an hour, and rinse. My stain took only one application to make sufficiently invisible, but it worked much better than I had expected.
posted by dhartung at 4:49 PM on July 27, 2011

Trisodium Phosphate (TSP) will remove any oil stains whatsoever. Available in a powdered form in a cardboard box from your local Lowe's or Home Depot. (May vary by state.) Mix with water in a 1 cup = 1 gallon strength, then apply to the floor with a mop until the water stops beading on the concrete. Keep a separate bucket of water for rinsing (or a hose) after you're done; TSP is a bit harsh on skin or dog paws or whatnot.
posted by SpecialK at 9:22 PM on July 27, 2011