Now most plastic cans that can be discarded after use are affixed with a number (from 1 to 9) that indicates the type or quality of the plastic. The plastic with the lowest number is the easiest to be recycled by the recycling factory, and the one with the highest number are rarely recycled. 
At present, the cost of collecting, sorting and recycling discarded plastic waste is higher than that of new plastic products made from raw materials.
 consumers can refuse to buy products that are packaged in the highest-numbered affixed plastic products to significantly reduce the long-term non-recyclable waste.