Use a light hack saw blade to cut them off. Wrap the surrounding tube w/ duct tape to avoid scaring. Make a couple of cuts if you have to.

Then use some sandpaper wrapped around the tube to finish. Wrapping the sandpaper will preclude you from making flat spots on the tube. Start w/ coarse and work to fine. When you do this, motion is like doing a shoeshine buff.

Practice on a crap frame until you get confident.