1. Sense of smell: It smells very light, but there is a slight plastic smell, mostly products of better quality; it smells strongly of plastic, and it is mostly products of slightly lower quality; it smells strongly of plastic and has a pungent smell Most of the taste is poor quality goods.

2. Tactile sense: touch the edge of the product, there is no thorny feeling, the edge is relatively clean, the mold is better, and the flash repair is also better; it feels rough to the touch, and the edge is rough, which means the mold is poor.

3. Vision: Transparent and colorless products look very transparent and free of impurities. Products with better quality (mostly produced from raw pellets) such as fresh-keeping bags, cups, lunch boxes, and fresh-keeping boxes; Products with a lot of impurities are of slightly lower quality (mostly produced from raw powder materials), such as sorting boxes, basins, hangers, and stools.

Most of the opaque products are products with poor quality (most of them are produced with recycled materials, but the recycled materials can be divided into many types, such as the recycled materials produced by the manufacturer's trimming; the defective products returned by the dealer to the manufacturer) such as trash cans and garbage Products such as barrel liners and garbage bags.