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Fill an old sock with uncooked rice. Consider adding lavender oil. Heat it up in the microwave.

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The most simple method for a reusable rice-filled heating pad. It just requires and old sock, some rice, a microwave and something to tie or sew the sock shut. First of all get hold a a good sized clean cotton sock that you won't miss, and then pour in the rice. There is no fixed amount of rice to use, but it is recommended that the sock be at least half or three quarters full. Don't overfill it though. There should be a bit of flexibility so that the pad can rest comfortably on your skin. You want it to be able to mold itself to the shape of your body a little. Some alternative fillings to rice include corn, barley, oatmeal and beans. If you are making a heating pad to try to soothe your headaches, you can add some herbal ingredients to help. The most commonly cited extra ingredient is lavender oil. Simply mix in a few drops, 4-6, of essential 100% lavender oil in with your rice. It's best to mix this in before you put the rice in the sock. Other suggestions for herbal additions include marjoram, rose petals, and rosemary. You can use dried herbs. Now you have made your rice sock all you need to do is heat it up in the microwave. Simply put your secured sock in the microwave and heat it up. The length of time you will need to put it in for will depend on the size of sock and amount of rice you have used. One and a half to two minutes should be long enough. Keep an eye on it and don't leave it unattended. As a safety precaution you can put a cup of water in alongside the sock. If you have added dried herbs, this is a good idea.