Being just a dumb homeowner, I am very unfamiliar with Pressure Washers. However, I bought a new PW w/ 13 hp Honda and Cat pump (4,000psi./4 gpm.). I have used it a couple of times so far to PW a pressure treated wood deck and to clean viny siding on home. Also, I had some experience using it to clean the concrete drive but was unhappy with the results as I apparently wasn't using the proper chemical and therefore, it didn't brighten to my satisfaction. My questions are... 1. What is a M5 X-Jet and what does it do that my 24 ft. extension wand won't accomplish? 2. Any good home recipe's for chemical to clean/bleach/whiten concrete driveway? I'm sure my PW has plenty of power but I'm clearly not using the right chemicals....even the house wash sucked. Nothing seems to clean the black streaks on the aluminun gutters. Any ideas???