Exfoliating or smoothing rough skin on the feet should be done:

Rough skin and calluses on the feet should be smoothed using appropriate foot files or treatments, applied gently to avoid injuring the skin — not cut with a razor or credo blade, which is unsafe and restricted in many places. Over-aggressive work can break the skin and cause bleeding and infection risk, which is especially dangerous for clients with diabetes or poor circulation. Knowing the safe, gentle approach to callus care (files/treatments, not blades) is an important pedicure-safety point on the exam.