CND Cucumber Heel Therapy Callus Smoother 236mL/8oz Professional-strength serum with concentrated alpha-hydroxy acids breaks down tough calluses in minutes. Regular use helps prevent new calluses from forming. Directions: Apply to calluses on foot with a plastic-backed cotton pad and wrap foot in a towel. After 5 minutes, gently rub treated areas with a Callus Smoother tool, then rinse foot thoroughly in bath. Rinse hands after application.