Hi Shirley, here's some help in the following article.
My son uses dish Dawn and a hot water power washer. He does it professionally.
Hi Shirley: What I used in the past, and successfully, is a product called LA's Totally Awesome Orange All-Purpose Degreaser from the Dollar Tree. It works just as well as the Green Magic that costs a lot more. It got the grease and oil from my garage floor from a car that sat there for 15 years! It's not as clean as I'd like it, but come on, 15 years! If your stain isn't that old, I'm sure you will have fantastic results, too. Good luck
Wet the area, cover with baking soda, then pour a Coke Al over it. Scrub with a stiff brush and power wash it off.
Shirley: I have found that whichever cleaning method you use... first put down kitty litter... to absorb most of the oil.