Oil stain in concrete

[Art]

Any suggestions on removing or at least improving the appearance of an old oil stain in a concrete driveway. Thanks.

[Joe Bobst]

Your neighbors will all understand if you park an Italian car over the the spot. An old Alfa Romeo will be very much at home covering the blemish. If you live in an upscale neighborhood, the Ferarri F430 is a good choice as they won't be looking at the concrete then. Otherwise blacktopping over the whole thing may be the only effective solution. Good luck.

Joe

[Bob]

appearance of an old

You could try scrubbing it with "gunk", which is a grease removal from the car parts store, or "goop", which is a waterless hand cleaner. Then rinse with a hard water spray or pressure washer. My best guess before any research.

OR:

All easily found with a google search for "remove grease from concrete".

Bob

[Art]

Yeah I found and knew about the cat litter one but I've heard it doesn't really work and I figured the different web sites are just researching it from each other. Was looking for some personal experiences out there.

[George E. Cawthon]

You might want to try spray on oven cleaner. My kids former car leaked like a sieve, so I would throw sawdust on it every time he left, but every 6 months or so I would have to do heavy duty cleaning. It might take two or three sprayings and washings if there is a lot of oil or a deep stain. And you may still need to rub it with a pumice block or a brick and kitty litter to get the cleaned area to blend with the rest of the area.

[Phisherman]

Pressure washing or Dawn dishwashing detergent. Concrete driveways are supposed to have (some) stains.

[Joseph Meehan]

By itself it is good for getting up the oil on the surface of the concrete. It does not get the stain out. However combined with naphtha it does a good job. Add the cat litter, then soak it with the naphtha and keep it damp for at least 5-10 minutes. Note: the old style, non scoopable, stuff works best.

Nothing is going to get it all out.

If the stain is in a garage, I suggest using a good epoxy (two part) garage concrete floor paint, following the instructions exactly. Then the oil will not be absorbed and you will be able to clean it up.

[trader4]

There are cleaners sold at home centers specifically for this. Look in the section with driveway sealers and/or paint.

[Art]

Would you be talking about the old fashion highly caustic over cleaners or the newer less caustic ones. Thanks.

[Art]

I tried one. Mediocre results on a different stain.

[m Ransley]

The grease can be removed but surrounding area may be noticeably different, It depends on how clean you need it and if it just for looks.

[Chris Hill]

Cat litter works, just put it down and keep walking on it.

[Capt Retardo and the Skidmarks]

Previously in alt.home.repair, "Art" proclaimed :

Muriatic acid. Pour on full strength, let sit about 5 minutes, hose off. Be careful of splatter and fumes. Works very well.

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[effi]

the oil is in the porous concrete so you may never get the stain out

most of the techniques mentioned so far seem to have abrasion as a common theme, and will probably involve removing a little of the surface cement from the concrete, by rubbing it with a brick, etching it with toxic muriatic acid, or using a pressure washer on it

anything you use (chemicals, etc.) to clean concrete that does not evaporate can penetrate the concrete

using chemicals then flushing them off the concrete with water after cleaning can introduce toxic pollutants into the water system

removing some of the surface cement will:

1. make the slab thinnner (even if only by a mm or two, possibly of no significance)
2. reveal more of the small rocks and pebbles in the concrete (as opposed to the smooth surface the cement was)
3. open the pores of the concrete so it is susceptible to more stains, from oils, grit from asphalt roofing shingles, dirt from car tires, stains from plants, etc. (unless you seal the concrete with a sealer, clear or stain or paint colors)
4. make the treated area different in appearance than the rest of the slab

quikrete makes products you may find of interest:

concrete cleaner

it is "Non-toxic, non-flammable and contains no acid.")

concrete sealer (clear)

these are made for concrete, and should outperform other products not made for concrete, kinda like washing a car with car washing detergent vs. diswashing detergent (the latter being a terrible idea, it ruins paint after enough washings, look at all the faded paint jobs on cars)

there are other companies besides quikrete that make products (cleaners, sealers, etc.) specifically for concrete

sealers (clear, stains, or paints) are applied after cleaning concrete to help make the concrete more impervious to absorbing stains

[Art]

For posterity, if anyone is reading this link, concentrated muriatic acid will dissolve concrete and ruin your driveway.

"Capt Retardo and the Skidmarks" wrote in message news: [e-mail]...

[George E. Cawthon]

Yep! Standard spray on oven cleaner that contains sodium hydroxide (lye). Stand up wind so it doesn't get in your eyes and nose.

Art wrote:

[bumtracks]

yea, cat litter works, the stuff at auto supply works a little bit better. I can't tell you how many times I've yanked engine/transmissions and forgot to drain trans oils ... best way to get it up has always been slide around in it on your back for a while, seems the pores on your back really sop it up quite well, then sprinkle on the cat litter to soak up the remainder - followed by more cat litter and chubby checkers Twisting the night away playing loudly will get everybody dancing. Hard on leather shoe soles though. Sweep it all up, look at your new girl friend and ask her to join you in the shower because you need help scrubbing your back.

[raven]

Spread used oil over the rest of the drive way untill it matches the old oil stain. Start in a inconspicous area first untill you have the technique down. Then do the whole thing.

John - that or don't get so uptight about a driveway.

[K. Collier]

Jeez, Never use it full strength. 4 parts Water to 1 part acid will be plenty strong. Use an acid brush and always add acid to water when mixing

[Oscar_Lives]

No shit. Everyone knows that pure hydrofluoric acid is the best.