The next time a cotton sock goes missing, take its clean mate and fill it with uncooked rice, be sure to leave some room for the grains to move. Tie or stitch the end closed. You now have a a great hot or cold compress.
To use microwave for 1 minute, check for any super hot spots and apply to the ailing body part.
Alternately, it can be placed in the freezer for an hour before use.
I find these are a lifesaver for sore muscles or tension headaches.