Whatever Shall I Do With All These Tubes?

Over the past couple of weeks at my workplace, I have been unpacking and installing a lot of small air system regulators.  Each one comes with a couple of short cardboard tubes protecting the ends of the units.  I've accumulated bunches of the things.

I'm thinking some sort of knock-together scratch-built ring-finned model rocket.

Also, the smaller diameter tubes look like they just might be a slip fit over a BT-50 tube.  Lots of possibilities there, too.

Must don my tin-foil, imaginative-thinking, odd-ball-model-rocket-designing headgear.....