+1 for mink oil. This is what I've always used. A good heavy coating on the leather, and work some into the stitching that attaches your soles to the leather as well. I've done everything with mine and never had my boots soak through. Mud/rain at the ranch, pheasant hunting in the panhandle with snow on the ground, hell even tromping through snow at the base of the mountain before putting my ski boots and skis on to hop on the lift. It will wear off after a while though, so reapply once or twice a year or so.