1, first you can soak it in warm water, then break it by hand or squeeze it, and finally dry it in the shade.

2. Secondly, you can dip cotton in warm water, then roll up the book cover, soak it in warm water for a while, let the book cover soften slowly, then straighten it and put it in a ventilated place to dry.

3. Finally, you can fill in the gaps in the book cover, and then fix the damaged parts with materials such as adhesive tape and inflating agent to ensure the integrity of the book cover.