He said he tried a bunch of stuff yesterday, but this does seem to make it go away completely.
The redneck said to not do that with a big stain because it would heat the concrete so much it would crack.
Slowly go over all of it, never staying in one place too long?
This guy talked too much too slowly, needed to wear sunglasses, tried Crud Cutter and Zep and then told us to tell him which worked better. Nobody seemed to think either worked:
There is a channel called Forever Alone that runs a professional pressure-washing business. They recommend
Dynamite Degreaser, $36 a gallon. This guy used Purple Power, brake cleaner, and acetone, and none of them worked very well: