Get to know the Diamancel foot file.  Its the best tool I’ve found to smooth feet and prepare them for topical treatments (ie, ARCH scrub/creme/oil!).  It is light in your hand, and it’s broad surface makes filing large contoured surfaces of feet like heels and metatarsal pads (ie, balls) fast and easy.  The best part is that it’s easy to clean (I recommend soaking for 10 mins in an alcohol solution), and it will last for years.  Yes, it takes a little effort in that back-and-forth motion, and there is no receptacle to catch that skin ‘dust’, but you will be happy enough with the results to endure the inconvenience.  For best results use on dry skin.  So, take a seat in the bathroom while your shower is warming up, and diaman-file away.