Why not use them for a wrap? I just started putting them on the battery in order of color to create a rainbow effect. They also have these hair ties in black some places, these were bought for $1.00 at the Dollar General store.
The ties hold really well and don't slide around, it also gives you a nice grip and you'll have hours of fun creating different patterns!
It's not often you can get a nice wrap for a buck, plus improve the draw of your Protank at the same time!
Update July 11, 2013: Check out my new Store at The Vapor Lady Lounge Store