I've used muriatic acid in the past and it worked well, Fred. You have to use a really firm steel bristle brush though...and wear your goggles so you don't brush the acid into your eyes!

Good luck!

Good question. I Googled and found this

https://www.concretenetwork.com/fix-concrete-cleaning/

Sorry about the oil stain left by a visitor, Fred Griffin Tallahassee Real Estate 

It looks like you got some good suggestions. I too, would worry about removing the oil stain only to be presented with a stain from removing the oil stain.

It can depend on how long it's been there and how deep it's penetrated into the concrete. Acid can eat away the cement if you leave it on too long. You can try Dawn and water to start. if that doesn't do it well enough, this product should work. A poultice will draw the oil up and out in many cases. http://www.diedrichtechnologies.com/architectural-specialty-cleaners/aspir-solv-safe-solvent-cleaner

I was thinking Dawn, but Debe's response is a good one too.

I had a seller use a bottle of dawn and a power washer. Worked well. 

Luckily I don't have a problem with that since my car does not require oil, but I keep kitty litter around for anyone that drips oil on my driveway.  If I get it on there soon after the drip has been made, the kitty litter absorbs it and doesn't leave behind a stain.

On an episode of Flip or Flop, Tarek's mom said this (and her process worked):  "So what you do is you put some water on the stain, then you sprinkle your baking soda, and then you get a can of soda pop and you put your soda pop on top of that, and then it's going to fizz up," she tells him.

"Then get a wire brush and use it on the stain. That should work. And if it doesn't work the first time, try it two or three times. Better to try that than having to redo the whole driveway."

Hi Fred... I've heard Pinesol is a good cleaning agent.

One day instead of oil leakers we will have electric cars thus no more stains

The search engine on Youtube, or Google would likely be as effective or more than asking AR, however I do see a few good responses here.

Hope you got the stain out Fred.

Brian's idea does work & I know that I have seen brush on stuff at Home Depot but have never used it.  You might end up with a clean spot.

There is no way to remove the stain that does not leave an equally obvious blemish on the surface. That means one needs to plan the remedation with that in mind. A checkerboard pattern of alternating texture could work...or do what 30% are choosing .... PAVERS.
Rather than move folks are investing  $12,000+ in drivway pavers that wrap all the way around the house to the 24x40 rear patio.

Doug Dawes has you on the right road!

Try a propane torch. It will burn away most of the oil, even the stuff down inside the concrete.

Fred,

Here is an article I found on line from Auto Zone.  I have also heard that cornstarch absorbs oil.  Wishing you all the best.  A

Are you certain it is only oil not transmission fluid? Is the driveway on a slope? Where I live I feel it is awful to put chemicals down the sewer drains as our pipes go to the ocean. I would make a little dam with sandbags (can fll with dirt) or old towels first. Big box baking soda, blue dawn soap is first treatment. Cover app the stain with 1/8 inch baking soda. On hands and knees scrub with an old bbq brush or wire brush you will throw away. Scrub and clean with trow away rags. Apply a second time and use the bottle of dawn to make a paste. Scurb again, clean up the now brown paste with rags that are a little damp.  How does it look?  Now it's time for chemicals. Wear pants, rubber boots, goggles. Goof off spray the stains. Allow to sit don't let it dry. I have a presssure washer and it's easy to use - I would use it on wide low setting to not grind off the top of the concrete. Keep tip about a foot away.  Let the driveway dry out to see how it looks. Go back over with power washer on all the driveway. Rust I got a different idea. They can seal the driveway with a garden sprayer or big wide paint roller.  Don't let people park on it for two days.  

Time and heavy rains were the only thing that's worked for me.  Tried the acid and wire brush like Debe Maxwell, CRS mentioned, even tried specialty driveway cleaners. Nada.

Gosh, Fred Griffin Tallahassee Real Estate - I am sorry the visitor (1) parked in the driveway and (2) left their calling card - dripping oil. 

I would Google it and find a solution that works best for you.

A paste made up of water and laundry detergent can work miracles sometimes and it doesn't damage the concrete. Firm brush bristles should be able to reach into the nooks & crannies. Old toothbrushes work well for smaller stains. Let it set in for an hour or so before rinsing. Good luck!