`Typically when you bring your bike or wheel to a bike shop for them to fix they tag it. One of the local bike shops I go to use an adjustable plastic clip which they usually leave on when you pick up you item. I started saving these realizing their usefulness but not really knowing what I would use them for. This past winter I have been cleaning up my bike work area. Trying to organize all sorts of bike parts and hardware that I had scattered throughout the garage. I finally found a use for these clips.
These are perfect for retaining small round parts (spacers, cogs, lock rings, even small washers), they're adjustable, and they were free! These can also be used to retain headset parts and even cassettes. Now whenever I need these parts I know exactly where to look.