I love flip-flops and bare feet in summer; unfortunately, my feet don't hold up as well as they did when I was a kid. Cracked heels, thickly calloused. They feel like sandpaper, and even twice monthly pedicures do little to keep the cracking skin at bay.
I have found my solution:
I know you've probably seen the commercial. It's an ergonomically designed cheese grater for the feet, and it works wonders.
I got it for $9.99 at Bed, Bath and Beyond (that place really does have everything). I probably could have bought a cheese grater, but I don't think cheese graters are ergonomically designed for grating feet.
Go, buy it...you won't regret it.