You're going to get a TON of 'you should've weaned already' responses. *just a warning*
But my son started doing this. As he bit a hole in one, it got tossed. As he got down to the last one, we warned and warned and warned..... When he bit through the last one [just before we went camping], he didn't get another. It worked. We'd tried weaning him before that and he had NONE OF THAT! It was a week of HELL when his pedi said, "Apparently, he isn't ready. He'd be over it in a few days at most if he were." So we gave it back and it wasn't until just before his 3rd bday that he was ready. I was surprised by how easy it was, but I think the warnings of him biting through them helped [believe it or not]. He knew when he was down to the last one.