On the first picture you can see my necklace.
It has goat skull with twisted horns.
I made it with fimo clay and paint it with acrylic paint. Use sponge for painting (you'll get "the dirty look" of skull, because paint will be only in the scratches).

On the other picture you can see pendant with straight horns, it was a present for my friend.

The other two pics presenting pendants without paint, first is without horns (I added them after finishing the skull using a small piece of wire for better hold).