We always cut the very top ring off (the "nub" on the small end). That
part is the only part that gets worn down over time and crumbles into
tiny pieces (or not so tiny) as they chew, as far as our experience has
been. I just take kitchen shears and cut, it comes off as a tiny ring
so do it where you can find it as it flies off ;)

[Posted in FML 7198]