I've used a rice bags for many years. Heated up in the microwave, it is perfect for a bad headache. I never thought of putting them in the freezer for a cold pack until I read this article from The Pistachio Project. The article gave me some ideas to make bigger ones to wrap around your neck for a neck ache and would be awesome to wrap around my arthritic knees that are very painful at times Click here for the article!