I recently tried it, and mind you I have somewhat mild Reynaud's (this is a phenomenon when you get super cold, sometimes blotchy hands and feet). I know nobody enjoys these, but this was ripping, unbearable pain, just to put my feet in. I made it one minute.
Is there another alternative? Although I'm sure my legs would not enjoy it, the sticking point is getting past my FEET. First aid style ice pack on quads?