Nails should always be filed when dry to ensure smooth edges.Place the sapphire file under the nail edge at a slant and file in one direction only.Back and forth filing may cause cracking and splitting.For best results,nails should be filed into an oval shape following the contour of the fingertip.Filing into a point wewakens the nail.The may be rinsed in warm water to remove residue:Allow to air dry.