How do we clean our concrete driveway after having work done on our car?

We had a friend come and replace our rear brake pads and drums on our car. When they were off he banged on what was remaining to clear it of dirt/buildup/etc. One side I swept up pretty good but the other side was run over afterwards and there’s a large black spot from the dirt/rust/buildup. How do we remove this from our concrete driveway?