If you do not take the horns off the base, they will rot. There is cartilage between the bone and the horn - a large spongy pad of tissue. They have to come off to be cleaned up. Any horned animal will have the horns removed in this way.
When you put the horns back, something has to fill up the space between the horn and smaller bone core that is now missing it's cartilaginous pad. Paper towels happen to work.
Have you ever dealt with a horned animal? I guess not.
