What Causes Black Marks to Return After Driveway Cleaning?
Black marks can return after driveway cleaning even when the surface looks spotless immediately after washing. The reason is that cleaning removes visible material from the top, but it may not eliminate the source of the marks. Residue can remain in porous concrete, organic growth can regrow, and new grime can arrive from vehicles, trees, roofs or surrounding surfaces. In Unley, where driveways may be exposed to leaf litter, vehicle deposits, damp shade and seasonal weat