Wet sanding sucks , I know, but you can't take any shortcuts. The amount of prep will determine how good or bad the final result will be. I've seen way to many people just grab a can of paint and shoot it on top of dirt and grease and then complain when it chips off. Hang in there . I've wetsanded my mustang by hand before and it really sucked so I didn't think the blaster was too bad.