James,
What specifically is wrong with the tip?
I work with Ebony all the time, Black, Brown and Macassar.
If it needs sanding and buffing, that is easy. If the tip currently has a finish on it, you'll have to match that after sanding. Or, sand the whole tip till smooth, and buff it for a nice finish. Ebony has oil in the wood, so no finish coat is required, but it is nice. Finish sand with 600 grit, then buff, or apply an oil finish.
Martyn