How to tell apart good and poor quality of cling film

We are very familiar with cling film,. There are good quality cling film and poor quality film. How do we tell apart?

1, Notice the packaging: If there is no "QS" logo, code and manufacturer's detailed address, you better be careful.  Those marked "PE" or "polyethylene cling film" can be used; With those marked "PVC" or  no raw material mentioning, you better be alerted. 

2, Notice the color: Yellowish means polyvinyl chloride (PVC) material, white for polyethylene (PE).

3, Hand rubbing: PE plastic film is with generally poor viscosity and transparency, easy to open apart after hand rubbing, while PVC plastic film is of good transparency and viscosity, hand rubbing is not easy to unfold.

4, Burn it: Getting PE cling film lit, the flame would be yellow, quickly burnee, not easy to get off, there are oil dropping phenomenon and candle burning taste; And PVC film is not easy to ignite, the root of the flame has light green and black smoke, will be extinguished after leaving the fire, and there is a pungent odor.

5, Buy them in supermarkets: PE cling film is mostly sold in supermarkets.