Oil does not simply sit on top of concrete. It migrates into pores and may continue wicking back toward the surface after the visible residue is removed. Asphalt introduces different limits because aggressive heat or pressure can damage the pavement itself.
Age changes the result
Fresh contamination is generally easier to contain and treat than a stain that has penetrated and weathered for months or years.
The surface matters
Dense, finished concrete behaves differently from porous, damaged concrete; asphalt requires its own conservative approach.
Treatment is a process
Compatible chemistry, dwell time, agitation, heat and controlled rinsing may be combined, sometimes across more than one pass.
Improvement is not a guarantee of erasure
A responsible proposal explains likely improvement, possible shadowing and the risk of a cleaner spot against uniformly weathered pavement.