... times till the liquid inside turns to solid and release heat. (If the bag is solid, pls follow “Use for ... solid, you can press the bag slightly to spread the heat evenly so that the temperature is even too.3. Place ... minutes. If you want to use it again, please heat it in boiled water for 5-7 minutes with towel ... the fridge and place it to necessary part. Hand Warmer, heat pack,cold pack,cold compress