Dou you have really hard cracked skin on your heels?
Use an electric sander on your feet. Use a medium grain sandpaper. It gets a bit warm and creates a lot of very fine white dust, but works perfectly.
( sandettie light vessel automatic New Twitter - @bollocksreally, Thu 27 May 2010, 13:33, 3 replies, latest was 15 years ago)

And have a phone within grabbing distance to call an ambulance with.

( idonthaveafunnynickname Drink-Aware? Sure. I'm aware I want another drink., Fri 28 May 2010, 18:19, Reply)

Cobblers
It works fine. I used one of those orbital sanders where it has a flat plate that vibrates about. You don't need to apply much pressure. The little grey stone we had in the bathroom was useless, and too much effort.

Only works though if your skin is really tough.

The downside is that I used to use the hard skin to scratch my other foot/ankle/lower leg if I got an itch when in bed. Can't do that now.
( sandettie light vessel automatic New Twitter - @bollocksreally, Sat 29 May 2010, 1:37, Reply)

nail the little grey stone in place for itching purposes
( enoughblueskyforsailorstrousers, Mon 31 May 2010, 0:13, Reply)