What can help extreme dry cracked hands and feet?

My favorite treatment came from an emergency room doctor. He suggested a half and half mixture of vaseline and pure beeswax. Melt them together in a microwave safe container (careful... the liquid is VERY, VERY hot). Pour the melted mix into a container to harden. It will become quite firm. At bedtime, dig a little out with a clean utensil or your fingernail and put it in the palm of your hands. Your body heat will soften the mixture so you can rub it into your skin. Be generous. Water will bead up on your hands after using the treatment due to the wax content. Putting socks on your hands before going to sleep helps, too. I like it better than just vaseline because it's not so greasy, and a little goes a long way. I also put on surgical exam gloves (non sterile) when I shower in the morning. The wax mixture will wash off with warm water and soap, and can leave a residue in your hair if you wash it after doing the treatment. The gloves keep my hair free of the mixture, and the mixture stays on my hands despite the soap and water.