"No. 3" PVC
Rarely used in food packaging, it is best not to buy.

"No. 4" LDPE
Cling film, plastic film, etc.
Do not put plastic wrap on the surface of food and heat it in the microwave.
Use: The heat resistance is not strong. Usually, when the temperature exceeds 110 °C, the qualified PE plastic wrap will appear hot melt, leaving some plastic preparations that cannot be decomposed by the human body. Moreover, wrap the food with plastic wrap and heat it, and the fat in the food can easily dissolve the harmful substances in the plastic wrap. Therefore, when food is put into the microwave oven, the wrapped plastic wrap must be removed first.

"No. 5" PP
microwave lunch box
When placing in the microwave, the lid should be removed.
Use: The only plastic case that can be placed in the microwave and can be reused after careful cleaning. Special attention should be paid to some microwave lunch boxes. The box body is indeed made of No. 5 PP, but the lid is made of No. 1 PE. Since PE cannot withstand high temperatures, it cannot be put into the microwave oven together with the box body. To be on the safe side, remove the lid before placing the container in the microwave.