Whoopie beads?

[L.D. Cakes]

Rubber washers.

[flight_chick]

Thanks Flight Chick, I'll take you up on that!

Hope you don't mind a mix of "pretty" colored one's. They are on the way...be on the look out for a small yellow envelope.

[brianfretz]

I used these. I found them at my local Boy Scout store.
http://www.scoutstuff.org/glow.html

It was a struggle to get my 1/8" amsteel through them. But the 7/64" fit just right. Plus they glow in the dark, and they are cheap.