Earth Therapeutics Filing Block Description: Four sides: Course, medium, fine and superfine. This unique filing block has four surfaces, from coarse to superfine, perfect for smoothing down rough, dry skin and calluses. Also effective in sanding down rough edges around the nails. To Clean: Rub lightly with nail brush under running water. Disclaimer These statements have not been evaluated by the FDA. These products are not intended to diagnose, treat, cure, or prevent any disease. • Add this colorful, multi-task filing block to your manicure set. Each of the four sides delivers a different degree of grittiness: coarse, medium, fine and super-fine. Does everything from shaping nails to smoothing dry patches and calluses.