A sharp drill bit and and a long life on your cordless drill will work. Literally just drill down the center of the rivet. The head will come off first and allow you to push the rivet through and release the snap. Honestly. All my boats have been screws on the snaps, never used rivets. Make sure you use like a flare rivet so it expands behind the fiberglass and isnt pulling on just the area surrounding the hole. When it gets brittle, and you go to pull on it, the rivet will come out if you are just using an Avex style rivet.