PM me how to repair ivory ferrules. I have some with small cracks that I'd love to repair before they get worse, if possible.
Roger Petit made me a shaft with ivory ferrule. It was his first ivory ferrule and an old cracked cueball was the source. The ferrule had a slight crack on delivery and Roger pointed it out with, "if it fails I will replace. I used the Crack (and still do) as A front sight. Keeping the Crack as the side to strike whitey on any off center strikes.
My treatment of the crack in ivory started with acetone to penetrate then super glue. Acetone is solvent for super glue and my theory is it allows the super glue to penetrate as deep as possible in the fissure. So far so good

But it's only been, uh roughly 35 years.