Hot / Cold Pack I. It is available for hot or cold compress. 2. For hot compress, please put in the microwavable container or cover completely with water at medium power setting for 30 seconds interval each time until reaching the required temperature or soak into hot water approx. 80-90 degree Celsius for 3 - 5 minutes. 3. For cold compress, please place it in the freezer for an hour before using. 4. Non-toxic, Non-caustic.