If you are referring to just the thick skin on plantar and palmar surfaces, jojoba oil is good. A little bit goes a long way. The same applies to eczema, psoriasis, and the like. I also like grapeseed oil, and coconut oil. I would not use mineral oil or any petroleum product for massage, as it clogs pores.
If you are looking for a good full body massage oil in general, that is a matter of personal taste, as well as client preference. While I tend to prefer organic ingredients, never has a client asked me for an organic massage product. More likely they are concerned with allergies to essential oils.
If you are looking for a good product for softening calloused feet, I have had good luck with Camille Beckman foot treatments. Not really an oil.
Some oils are more difficult to wash out of massage sheets. A neutral oil blend like the SpaMaster Essential brand is easy to launder out of my sheets. Biotone probably offers the largest variety of massage oil blends, but be careful you're not buying a niche product you will rarely use. Almost every natural product has a shelf life, meaning that it will eventually go rancid.
