If the stain is really set in, you might have to diamond-grind it to get rid of it.
Like I said, instead of crushing up oil dry or kitty litter, just use cement. It’s already a powder.
If it’s fresh, you can pour on a cup of gasoline then light it. Don’t forget the marshmallows!
I’d worry about muriatic acid doing more damage.
When I did concrete work years ago, we used diluted muriatic acid to prep a concrete floor for sealing or painting. I don’t think it cleans imbedded oil though.
I remember using that on my garage floor many moons ago. I had tennis shoes on (sneakers for east coast folks) and the heat coming up through the soles was like walking on hot coals.
There are people who pay Tony Robbins good money to do that.
One has to be careful about that clumping litter, it gets wet and turns into a slippery mess. I think it will go away eventually by itself, not sure of the time frame.
As far as muriatic acid, I’ve heard a ratio of 10 parts water to 1 part M. acid. I’ve seen someone on YouTube use a propane weed torch to burn it off. However, it was tranny fluid, on bricks and only a few days old. Took some time but it worked.
How would this be done?
Can you tell me how this is performed?
Yeah it’s powerful and dangerous. Nothing to play around with unless your real careful.
Sure. You either rent a diamond grinde, or you have a service come in and do it for you.
Here’s a video that shows how it’s done:
The advantage of diamond grinding is that whatever’s staining the concrete will come out because you’re actually removing a layer of concrete. The disadvantage is that it’s noisy, dusty, and if you don’t do it right, it’ll look weird. Were I going to this effort, I’d then top-coat the concrete with an outdoor-rated poly coat. That’ll seal it so that future oil leaks can just be wiped or sprayed off rather than having them soak in again.
You can rent a diamond grinder from places like Home Depot.
Another disadvantage of diamond grinding is it takes away the finished seal that is created when the concrete was finished upon pouring. The concrete might be old enough for that seal to be worn, so then it wouldn’t matter. If your going to grind the surface, it might be a good idea to apply a sealant afterwards.
I’ve used muriatic acid (dilluted per directions and a little stronger) on my garage floor. It bubbled (like…acid) and cleaned the concrete surface pretty well. It basically lightened (color) the entire surface. Oil stains…were lighter but still present. I wasn’t overly intimidated or impressed by it.
I generally use Purple Power degreaser. It does pretty well if you don’t dilute it. Gasoline is ok for small areas. You should stop smoking anyway 
.
Once the oil has sat there and soaked in, it’s just going to be there from my experience, short of removing some concrete (which I don’t want to do, myself).
If there’s a lift any stain magic elixir, I’d definitely buy it. Maybe spread used oil over the entire floor then clean it up. That way it’ll all match!
Same issue with the acid. However, I’m not sure if my garage floor was ever sealed as I couldn’t tell the difference before and after the acid wash. I assume if it was sealed in the first place it wouldn’t soak up the oil? Not sure. My concrete doesn’t bead water like a wax job on a car and never has. So I assume it wasn’t sealed…?
I’m like Bing. I love the look of those perfect, painted/stained/epoxied garage floors. But I’m afraid a bad job dressing it up could easily look worse than a few oil stains. And I’m too cheap to pay a pro! I should have them remodel the inside first lol. And my wife’s been eyeballing hardwood floors…
About everyone I’ve talked to has sections coming up from the heat of the tires after a few years, and yeah unless you do the diamond surfacing-just not worth it to me when you can put down a PVC tile floor for less money and replace one if you need to-I think at this point anyway.
As far as the muratic acid, I’ve used it to clean (as well as the pros) the excess mortar off of new brick work. Not sure what the dilution rate was but read the directions. Rubber gloves, eye protection, skin protection, shoes, etc. Nothing to fool with. And as always, you don’t add water to the acid, you add acid to the water-or is it the other way around? I’m not a chemist.
“it might be a good idea to apply a sealant afterwards.”
This was a wrong statement. I should have said paint. When concrete is finished, the trowel brings the cement to the surface leaving the stones below. When you grind the top layer of cement off, it leaves the aggregate exposed. It can look pretty cool but has to be done right or paint over it. I thought that by removing the cement seal on top might diminish a seal, but probably not.
I had mine professionally installed. I’ve had it for 3 or 4 years now and no signs of hot tire pickup. If it ever does, it has a lifetime peel warranty. The pros have licenses that let them get their hands on better chemicals than you find in the box stores, but you do pay for it. Prices are hovering around a little more than $1,000 per stall.
The nice thing is to do a complete clean of it, you just dump some mild vinegar/water solution on the floor, let it sit a few minutes, and then hose it out. I only have to scrub a little bit where the salt adheres from under the tires.
Always add acid to water
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The basic idea, good for new stains and old, is to use the solvent extraction method which many here have been describing. First soak the stained concrete with a thin solvent in which oil is soluble (a non-flammable paint thinner should work, but never anything like gasoline, which is prone to flashing explosively), cover with a fine grained absorbent powder (some kitty litters, baking soda, diatomaceous earth but don’t breath the dust, talc, corn starch, there are products sold for purpose but even non-oily, dry dirt or clay will work in a pinch. If you like you can make a paste of the solvent and powder and apply it to the stain.
The solvent will penetrate a little way into the concrete, dissolving the stain, and as solvent evaporates from the surface of the powder the oil laden solvent will migrate upward by surface tension into the dried powder, carrying the oil with it. When all is truly dry, brush or vacuum it away and repeat if indicated.
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