A brick factory producing aerated blocks in Guizhou has been engaged in the production of aerated bricks for 15 years. At present, it has an annual output of 2 million cubic meters. It is packaged and transported by pallets. The annual investment in pallets is very large, and the cheapest wooden pallets are also required. 60, 70 yuan a, and the loss is very large, the driver is not willing to recycle, the investment in the tray is more than 1 million a year.