If it is broken, it can be glued in the following way: 1. Apply thick ink (buy a bottle of ink and take the sediment at the bottom) to the section, press it hard, and then wrap it with transparent tape; 2. Mix the egg white with a little scallion juice, and then glue the slices; These two methods do not affect the use at all, but the adhesive strength is average. 3. Glue it back with white latex. This will affect the cross section, so it needs to be scraped and ground again, but it will stick tightly.
If it is not broken, you can drop thick ink into the crack and then wrap it tightly with transparent tape to repair the ink seam.