Buy Peter Thomas Roth Masks & Peels - Peter Thomas Roth Irish Moor Mud Mask 150ml/5oz. How-to-Use: Using fingertips, apply evenly on clean skin. Leave on for up to 10 minutes. Remove with a warm, damp washcloth and rinse skin thoroughly of any remaining residue. Use 2-3 times a week, or as desired. For external use only