Just finished a Pressure washing job in Alpine in San Diego county. It was a one day job. Pressure Washing services were never done at this location so the concrete was really bad. The concrete was stained so we had to be careful of pressure washing to close to the concrete because it could damage the stain. We had to scrape most of the gum because of this. If you just pressure wash the gum off stained concrete the pressure washer will take off some of the stain so you have to scrape it off. Then lightly pressure wash the concrete. Job came out very nice