I started to use those rings in a different way this year. I thread a line through one (as Jim wrote, use a safetypin!) and then form a dropper loop so that the ring hangs in the loop. Wet the leader and thighten. It's hard to describe what should happen, but the idea is that the ring sits thightly inside the knot at an angle, so you can easily replace the dropper when it becomes too short. I think this makes a stronger because the line stays intact.
(after rereading this, even I don't really understand what I'm trying to say here. Sorry!
)
Good luck!
Jeroen