In our daily life it is common for us to pile up so many used books. They have taken up too much room. So it is best for us to deal with them . Different people have different ways to deal with that. Some will throw them away. They think the used books are not worth so much , besides ,they have taken up too much room. Others would like to sell their used books because they think they can use the money for the old books to buy new ones.
In my opinion, we can give away these used books to the children in the distant mountain villages. They are too poor to buy new books and they need these books most.