Flakey Bison Horn...

The horns can definitely be repaired. There are several ways you could go about it, depending on how much you effort you want to put into it and how you are expecting them to turn out. (Bison horns are pretty rough sometimes on live animals) You could just sand them down with sand paper and take off some of the flaking outer layer and then paint with an airbrush. You could also try rubbing a little oil into the horn before and after sanding. It will help some of the rough areas and darken up the horn. If the cracking or flaking is really bad you can fill in the voids with carpenter’s wood filler putty. Let it dry, then sand it down to get it as smooth as you can and then paint with an airbrush to the desired color. I’m sure there are other methods as well, but these are things I have done with horns in similar situations with good success. Hope that helps…good luck!

 

A paint scraper or knife dragged sideways does a good job to smooth the ragged surface. Rasps and grinders are good, but they can leave deep scratches against the grain that will not look natural later.
You can do as much or as little as you like. The horn is really quite thick.

I worked on these horns a while back for a future mount. They were probably in worse condition than yours. Just a bit less splitting towards the tips.
The first picture was after some initial scraping, 2nd pic is after giving them a bit of a stain with black leather dye. And buffing with steel wool.
I think I will actually
Try to drybrush a bit more white/sand colour to make them look more rustic later when I get to the mount.