How to use a bunch of express boxes?

Mr. Chen, a citizen, is also an expert in online shopping. As for what to do with express cartons, his approach is to save them and sell them as scrap when they reach a certain amount. During the interview, the reporter learned that some people save their own express cartons and sell them, while some people specialize in recycling other people's express cartons. Ms. Zhang, who lives in a high-rise railway community on Yuejin Road, specializes in recycling other people's cardboard boxes and selling them as scrap. At 9 a.m. on November 16, Ms. Zhang pulled a shopping cart full of express cartons to the waste collection office. Zhang said that there are usually not so many old cartons recycled in a day. These days, about two loads of cartons can be received in one morning alone. Often, “I have just collected one load, and then turn around and the trash can is full again.” "Cartons", because there are too many cartons, she chooses not to accept some smaller cartons, because there are a lot of tapes on the small cartons, and it takes a lot of time to sort and flatten them, so she usually picks up the larger ones. Mr. Jiang, a citizen, is also engaged in waste recycling. He said that the recycling price of paper has been rising this year. Some time ago, the recycling price reached 2.8 yuan per kilogram. Although the recycling price has fallen back recently, it is still 1.7 yuan per kilogram. According to the recycling volume after the "Double Eleven" in previous years, it is not a problem for Chen to purchase 300-500 kilograms of old cartons every day, which is a considerable income.