Not just for sandal season. Keep calluses at bay while getting feet in tip-top flip-flop shape. Feet will not only look great, but will feel silky-smooth and super soft all year round. Tips & Tricks Soak feet to prep and help soften hard skin. While skin is still soft and damp, use the course side to exfoliate especially rough or callused spots. Use the opposite side to smooth bottoms of feet and between and around toes.