Wrap them is a hand towel and then put them on the bottom of the tub and then put a full size towel or blanket down on top of that. Also if you haven't done it yet, I would advise going to Home Depot or a hardware store and picking up a sheet of rigid foam insulation. the kind that comes in the 4x8 sheets with reflective coating on 1 side, the stuff used in attics and walls. I score it to the size I need and then break it and put it on the bottom on my tubs as it keeps the heat in and doesn't allow it get sucked up by the floor.