First,we need to know the color. If the whole roll is yellowish, it is usually made of PVC, and white is made of PE;

Second, rub it with your hands again. PE cling film generally has poor viscosity and is easy to open after rubbing by hand, while PVC cling film has better viscosity and is not easy to spread when rubbed by hand;

Third,burn it, the transparency, stretchability and viscosity of PVC cling film are stronger than PE cling film. When the PVC cling film is burned with fire, the flame will turn black, emit black smoke, have a pungent smell, will not drip oil, and will automatically go out after leaving the fire source. When the PE cling film burns, the flame is yellow, odorless, dripping oil, and can continue to burn after leaving the fire source.

In addition, the cling film should be removed before heating the food to prevent harmful substances brought by high temperature from penetrating the food. Different plastic wraps have different degrees of heat resistance. Some plastic wraps with low melting points will be damaged during the heating process. If it must be heated together, several small holes can be pierced in the bag to facilitate the evaporation of water and prevent the expansion of gas. Burst the plastic wrap.