This foot file removes calluses and dead skin to "make your feet feel smooth and healthy with NO MESS!" Powdery filings collect in a little compartment. Cost: about $10, sometimes with an extra PedEgg and buffing pads.
Twenty-six women and three men with rough, callused feet tried a PedEgg on one foot and a pumice stone on the other. They used each product once, rubbing PedEgg on dry skin (per instructions) and the stone on wet skin, where it's more effective.
Crack open a PedEgg. It was very good at removing calluses and good with dry skin. It did better overall than a pumice stone, and buffing pads smoothed leftover roughness. But some filings escaped, so use it over a wastebasket.