Oil stains on concrete

[Filliam H. Muffman]

For coarse finish concrete, just repeatedly grinding clay based kitty litter/oil absorbent with your shoe can do wonders if the oil hasn't soaked too far in. The dust picks up oil and the larger particles abrade the surface to reduce the darkening of the oil. You might need to feather it out if the surface is a special color.

A possibly drastic/overkill option could be to coat the entire driveway with a sealer to darken the entire surface.