lots of ways to erase oil stains
If its on asphalt,its much harder to get rid of oil stains than cement--muriatic acid works,but is deadly to pets and grass,and even one drop in your eyes will be disaster--I use speedi-dri on big spills first,when the majority is mopped up with that,Castrol Super Clean scrubbed in with a brush,or laundry detergent will help cut the grease,I've used easy off oven cleaner too with limited results---the bottom line is you aren't likely to get ALL the stains out with anything you use,but you can try TSP--Tri-sodium Phosphate,sold in paint stores,scrub it with a brush like the detergent--they claim if you cover the spill with speedi-dri,and soak it with paint thinner it will lift the stain into the speedi-dri as the paint thinner evaporates....
I've tried them all,but still have a big oily mess where my 82 GMC Cabalaro leaked dextron and motor oil on the driveway--one thing I've learned,its a lot easier to put a mat of cardboard or a peice of plywood or other stuff(homosote,, or masonite board will catch the oil,and once it soaks in you can burn it) under the car or truck,and to mop up any spills quickly,before they get to soak in--I've tried pouring lighter fluid on it,and lighting it,and letting it burn--it smokes like hell,softens the asphalt,but some of the oil did burn off,but the tar will never be the same!

--the only thing that will remove them completely is time--after 12 years,the spot my 72 K5 oozed gear oil all over the drive has no trace at all,except for a darker shadow where the 90W used to be--I guess acid rain and 12 years is one way to get those stains out!!...
