Stubborn oil-stained concrete.

[HydroBlast]

Oh wise power-washing gurus! Please help me with this reoccurring dilemma. I will power wash a parking stall (concrete) and it will look like you could eat the eggs that fried on them this summer. But..... the center line of oil stains remain. I've presoaked , Hot-water the begeeshes out of them, and stood on them with 3500psi 5.2 gpm to no avail. Tell me there's a secret potion I'm missing. Please tell me.
Desperate Dennis [wow]

 

[MR ALAN]

Dennis,
It is not uncommon for a shadow to remain after the concrete is cleaned. The dirty oil and all other soil is gone, but the spot where the oil was will be shadowed for a period of time, just like gum shadows on neglected concrete.
UV, & repeated cleanings will make it fade over time.
If the spots are fairly fresh, they often come out completely.

 

[Revive]

Oil stains are like ice burgs.What you see is about 10%. The other 90% is underneith. Degrease and hot water. Then "Natural Enzymmes". We can get rid of most of it if not all. Bearing in mind the expence of the time required. When we get called from a car dealership to remove the stain off a customers $50,000 interlocking driveway, is a lot different than the pad at a drive through resturant.

I ran across an oil spill the other week with a hasmat team there to do the clean. I started shooting the bull with the head guy. He is triing to say that he uses a scoop or two of portland cement, sweeps it around on the dry conrete after using an absorbant. Claims it takes the stain out. I'm not saying it will work, just that that was his comment. If someone gets a chance to try it before me, "PLEASE" post the outcome.