The Edge Duraboard 240/240 Grit File (x 10) is a fine grit file that is best for removing small bumps, ridges or discolorations and for shaping the free edge of natural nails. It is a washable, cushioned file providing a better grip, allowing for more control and faster refinement. Cleaning Instructions: Put nail file under running water and brush the grit surfaces lightly. Do not leave immersed under water for more than 10 minutes. Pat dry and allow to air dry for 24 hours before re-use.