does anyone use a flat surface cleaner on block paving? over the last couple of months ive been asked to a couple of jobs were theyve had there drive cleaned and its still left bits of muck on the edges of the brick, i know the company that did it has got a set up so there either using the wrong equipment for the job or rushing it. the main reason im asking as i was thinking of investing in one of these but 90% of my power washing jobs are lock block so i wont bother if there no good for it