Avoid sudden temperature changes. Do not place hot glassware on wet or cool surface. Allow hot glassware to cool on a cooling rack, potholder or dry cloth. Do not use on or under a flame or other direct heat source. Add a small amount of liquid sufficient to cover the bottom of the dish prior to cooking foods that may release liquid. Do not overheat oil or butter in microwave. Microwave and dishwasher safe. Plastic lids are for microwave and storage use only, and are BPA free, For more information, visit www.pyrexware.com or call 1-800-999-3436. Avoid extreme temp changes Hot/Cold.