Depends on the type of dirt / contaminants. For heavily soiled areas , it is always best to start with rinsing (ideally with a moderate amount of water pressure) to knock off most of the heavy dirt. I usually don't rinse the entire vehicle just areas where there is visible dirt build up (typically front bumper, wheel arches, lower panels and backend for vans/suvs with square backend). For general agitation of power clean before performing ONR wash, I will use a good quality microfiber towel soaked in standard ONR dilution ratio. I do not return this towel to my ONR bucket to avoid contaminating the ONR solution with PC. The ONR solution provides additional lubrication over just PC in order to minimize chance of marring. I like using the Minx (or Minx Royale) from The Rag Company as it is very soft and absorbent which makes it ideal for pulling dirt from panel in order to minimize marring. I will typically do a full rinse afterwards to remove PC residue but you could still try your method of drying with microfiber to remove remaining PC. When completing ONR wash if I notice any stubborn tar or bug guts remaining, I will pull out Jersey Bug Scrubber soaked in ONR and apply small spray of PC to surface of scrubber to attack that stubborn area. I will go over again with ONR from BRS to flush area and dry as normal.