So yesterday, I didn't find any second hand elastic, but I did find some tiny shelves:
Tiny Shelves; perfect for BOBBIN things, and THREAD things! That's the before pic, and I've worked out it can home over 60 bobbins of full sized threads, which will be just right for my stash (if you recall I had a few op shop finds, plus my friend donated all her grandma's precious stash, so my threads needed a new house!) Yay! I unsuccessfully hammered in a few nails, so Husbie says he'll make it a weekend project.
And, here are the sleeves, with proper elastic:
Cute & Milkmaid-esque.