You can boil it in Brown Rit dye or use an oil based leather dye. With the Leather dye I wipe it on and quickly wipe it off the see what I've got. Once I'm happy with it I heat the horn with a heat gun to set it. Both operations are followed by a coat of Brown shoe polish.
Others will have their method but this has work for me for years with no complaints.
Tim C.
The top one is done with Rit the bottom Dark Brown leather dye.
