After heating or hot compress for 60- 120 minutes, the bag gradually cools. If you want to use it again, please wrap the bag with a towel or cotton cloth (to avoid direct contact between the bag and the heating container), then put it in boiling water for about 5-7 minutes to make all the solids in the bag become liquid, and then take it out for use. At this time, because the bag body is in a high heat state, it should be wrapped with a towel or cotton cloth, so that the bag body should not directly contact the skin to avoid scalding.