The production of special bag material market may exist many differences, commonly used in production of materials including polyethylene film and PVC film, these two kinds of materials are non-toxic, but second at the time of production, will add some added materials, these add something has certain toxicity may bring harm to the human body, so when buying market special bag, the best choice is the first production of polyethylene plastic bag, and two bags of the screening method is simple, the production of polyethylene film bag feels very smooth, milky white, drop down something burning when there is thick, second bag surface feel sticky, even fire not easy to burn.