How do I remove oil and grease from concrete?

https://thesecretyumiverse.wonderhowto.com/how-to/7-diy-ways-remove-oil-stains-from-your-asphalt-driveway-0143497/

You sound like the next owner of my home. There are lots of products to try but, even if you prepare it to paint, I don't think that all of the visible stains will yield especially if the concrete was not sealed. I see that Quikrete has an oil stain remover. If anyone sells a product that has a chance, it is them. I would try that first.

Most hardware stores have bags of product that you sprinkle on oil & grease and you leave it awhile and it soaks up then you can sweep/scrape up

The only thing that we have tried that has been even partially successful is lacquer thinner and clay cat litter (not the clumping kind)

Pour the lacquer thinner on the stain and cover with a 1/2 in to 1 inch layer of clay cat litter.... pour more thinner on the cat litter and let sit until the whole thing is dry... sweep away litter and check to see how much of the oil has lifted... Repeat until all the grease and oil is gone... scrub the spot with baking soda and peroxide and a stiff brush..... It may not completely remove the stain... but i will lighten it up.

The one I found was on homedepot.com. I've not successfully cleaned oil stains from concrete so I cannot recommend anything in particular. I can tell you that liquid laundry detergent does not do the job.

WD-40. Did a leaky oil pan leave a big ugly spot in the middle of your concrete driveway? To get rid of an unsightly oil spot, just spray it with a generous amount of WD-40 and then hose it down with water.

Soda (Coca Cola). Here’s how to remove oil stains from concrete drive-ways and garage floors: Gather up a small bag of cat litter, a few cans of cola, a stiff bristle broom, bucket, laundry detergent, bleach, eye protection, and rubber gloves. Cover the stain with a thin layer of cat litter and brush it in. Sweep up the litter and pour cola to cover the area. Work the cola in with a bristle broom, and leave the cola for about twenty minutes. Mix 1/4 cup laundry detergent with 1/4 cup bleach in 1 gallon (3.7 liters) warm water and use it to mop up the mess.

Oven Cleaner. Get those unsightly grease, oil, and transmission fluid stains off your concrete driveway or garage floor. Spray them with Easy Off No Fume Oven Cleaner in the BLUE can. Let it settle for 5-10 minutes, then scrub with a stiff brush and rinse it off with your garden hose at its highest pressure. Severe stains may require a second application.

Kool-Aid. Nasty rust stains on your concrete? Mix unsweetened lemonade Kool-Aid with hot water. Scrub and the rust stain should come right out.

Baking Soda. Salt and commercial ice-melt formulations can stain — or actually eat away — the concrete around your house. For an effective, but completely innocuous, way to melt the ice on your steps and walkways during those cold winter months, try sprinkling them with generous amounts of baking soda. Add some sand for improved traction.

Ammonia. Tired of those annoying discolorations on your concrete work? To get rid of them, scrub with 1 cup ammonia diluted in 1 gallon (3.7 liters) water. Hose it down well when you’re done.