The pacifier presents a lot of dental problems. I don't think 2.5 is too young, however I do think it's old enough for HIM to do it himself. Tell him there is a special day coming up where he's big enough and finally gets to have Paci FREE day, tell him all kids do this when they get BIG enough. Make a big deal about it, offer cake and ice cream and set it up like a birthday party. It's HIS day and HIS responsibility to go around collecting them all, and throwing them in the trash.
We did this with our son, at age 3... if I had thought a little more creatively how to do it before his 3rd birthday, I would have.
Good luck!