I have done many, as it saves money (at the expense of time)

1) I use a Dremel to grind off the curled over side of the rivet. Then usually burn my finger since it heats up the rivet face, and I always end up accidentally touching it. Punch out the rivet.
2) replace the face with a new one (I have bought many from Bay Area Amusements)
3) rivet on the new face with a new rivet and backing washer- make sure you line up the vertical lines on the back of the face so it doesn't spin. I use a rivet tool that is like a c-clamp that I got off ebay
4) replace target foam