1, sold online. Books can be sold on online second-hand trading platforms such as idle fish, cave nets and multi-fishing. These platforms usually have a relatively complete trading mechanism, which can easily sell second-hand books to buyers in need.

2. Set up a stall offline. You can set up a stall in the community, around the school or in the second-hand market and sell the second-hand books directly to readers in need. This requires you to find the right place and time, but you can communicate with readers more directly and understand their needs.

3. Donate. Second-hand books can be donated to non-profit organizations, schools or libraries to help people in need obtain book resources. This can not only reduce idle books, but also transmit positive energy and help others.

4. Participate in exchange activities. You can participate in online or offline book exchange activities, exchange unwanted books with others, and reduce the number of idle books.