Fine Lines Nail File Sapphire Nickel in 4 and 5 inch length is a touch of pure elegance.The correct way to file your nails is to file from the side of the nail to the centre and then from the other edge back to the centre in smooth even strokes. Do not file in different directions. File (bevel) the top of the nail slightly flat if it becomes too pointed. Never file nails after swimming or bathing as nails are at their weakest.