Cleaned a driveway today, took ages, every time I think I've finished I look down and some of the joints are full of dirt, it's like I kept chasing it moving it from one joint to another. Now they want it sealed, will it be ok if some of the joints only have a few ml of sand on top of the dirt? Will the sealer just make the dirt hard as well? If so should be ok yes? I cleaned it with a fsc and then went over bits with a turbo nozel.