I had an ear ache one night and only had large rice bags. So I decided to make a quick one. Rice bags are awesome for minor injuries they provide moist heat that conforms to your body and they slowly cool over time so there is less risk of burns.
about a half a cup of raw uncooked rice (not instant)
One clean tube sock.
Pour the rice into the sock. It should just about fill the foot portion of the sock. Use a funnel to save a possible mess.
fold the sock over
tuck it into its self. As if you are rolling socks together. Try to use the whole ankle portion. Then adjust to make it look neat
Put your new rice bag into a clean microwave (or on a plate if your microwave isn't clean). set it for 30-45 sec. It will be hot handle with care also you can use a clean wash clothe to handle it with.