"Waterproof abrasive paper is a very good choice for clearing up minor irregularities in paintwork, or preparing for painting or polishing. One example is the RHODIUS WSP, which is available in 19 grit sizes. With a grain spectrum ranging from 60 to 2000, this offers the right grit for any purpose.
If the paper is placed in water for several hours before starting work, waterproof abrasive paper becomes amazingly flexible, capable of fitting easily to the surfaces of the workpiece. This also means that the sanded surface can be moistened now and then with a sponge, so as to simply rinse off the abrasive particles."