Alternate the direction of the tool---extractor,
vacuum, brush:
-Pull towards you to make one line (stripe); then:
-Push away from you on the next stroke of the tool...
making sure it's parallel to the preceding "stripe".
Editorial:
Although I personally don't care
for the "striped-look"...
I suppose it's to give the customer some sort of an
assurance/(impression) that every square inch of the
vehicle's fabrics...carpeting, mats, seating areas...
were totally cleaned and not just "spot cleaned"?
Bob