WetsandWetsanding can be done during the prepping process or after the paint is sprayed. If done after the spraying, wetysanding will eliminate any imperfections, it will also flatten the paint job, and help eliminate any graphic edges.ing can be done during the prepping process or after the paint is sprayed. If done after the spraying, wetysanding will eliminate any imperfections, it will also flatten the paint job, and help eliminate any graphic edges.