Set of 4 INCREDIBLE Novaculite (reconstituted from famed Arkansas novaculite stone) nail files. These files are designed for both home and professional use and should last the average user a lifetime. They come in four grades of coarseness for specific application: Blue file is medium for filing, the Green is for pedicures, the Yellow is for removing stains on your nails and the Pink is designed for gentle shaping. There is nothing else on the market that comes close to comparing to these amazing nail care products. To clean, simply wash and dip in alcohol.