3M Wetordry allows you to sand between coats of varnish and paint or other finishes. Can be used with water to reduce clogging and extend abrasive life. Ideal for sanding metal for repainting or prior to primer coat.3M Pro pak Wet or Dry abrasives are specially designed for wet or dry sanding. Use 3M Imperial Wetordry Sandpaper for a premiere finish on lacquers, primers, sealers, plastics and paints. For final or between coats sanding.