You can't. PVC and PE used in plastic bags and food bags are not heat-resistant. Once exposed to high temperature, harmful substances such as plasticizers will dissolve out, which is harmful to human health. Therefore, microwave heating must use special tableware, such as ceramic bowls, glass bowls and heat-resistant plastic bowls. Microwave is an electromagnetic wave. The microwave oven consists of power supply, magnetron, control circuit and cooking cavity. The power supply provides a high voltage of about 4000 volts to the magnetron. Under the excitation of the power supply, the magnetron continuously generates microwaves, which are coupled into the cooking cavity through the waveguide system. Near the entrance of the cooking cavity, there is a rotatable agitator. Because the agitator is a fan-shaped metal, it can reflect microwaves in all directions, so microwave energy can be evenly distributed in the cooking cavity, thus heating food. The power range of microwave oven is generally 500 ~ 1000 watt.