2. Some plastic boxes can be heated by microwave oven. However, it should be noted that plastic boxes made of PP need to be marked with a triangle arrow on the outside of the plastic boxes and the number 5 in the box can be used for microwave oven heating. In addition, special containers made of porcelain, pottery, heat-resistant glass, polypropylene and polyethylene can be used for microwave oven heating.

3. Ordinary plastic containers, metal containers, porcelain with metal edges and closed containers should not be used in microwave ovens. Ordinary plastic containers are easy to deform when heated by microwave oven, and release toxic substances, which pollute food and endanger human health.