I bought this big buffer foot file a while ago in a gift set with socks and foot cream. Expensive but it really does slough away hard skin leaving feet soft and smooth.
Bliss say "nickel-coated flexible fiberglass files, electroplated with industrial grade diamond chips, so they rarely (if ever) wear out. The Diamancel Classic Big Buffer is a gem of a sole-smoother which effortlessly buffs away scratchy skin".
Use on dry feet before shower/bathing. Bliss recommend using in conjunction with Bliss Softening Socks and Bliss Foot Control.
I use with cotton socks and whatever foot cream I'm currently using - either Liz Earle or my new Soap & Glory one I got from one of my bunny boxes.
Retails at (ouch) £39.90 but it really does last and last (I've had mine a good few years now) and it leaves feet feeling brand new!