Fire up the stove in the house, find your wifes best broiler pan, fill it with water, bring water to a boil with the horn in it, let boil until the horn starts feeling a little soft, then remove from water and sometimes, depending on the horn, you can just smack the horn on a concrete floor or wooden corner post works too, and the core will come out. Sometimes I find myself using a knife and sliding it in between the horn and the core to loosing it up. Once you get the core out, you'll need to know what you'll be using for a mouth piece. By knowing the diameter of your mouth piece will dictate how much of the tip to cut off. Once I have the tip cut off, I then begin sanding the horn. I use a 4 1/2" flap disc on my grinder for the heavy duty grinding, then I go to sanding by hand, eventually getting down to 400 grit. Size the tip so as to fit your mouth piece in and I use a two part epoxy to glue it in place. Also will want to sand the inside of the horn some and then seal it with something, I use polyeurethan(sp).
That'll get ya started, and oh by the way, I was just kidding about doing the boiling in the house, I'd highly suggest doing that part outside with an old pan that your wife doesn't ever use. /ubbthreads/images/graemlins/laugh.gif