I have the box that my Mah Jongg racks came in; long and skinny. When I clean up after cutting, long strips go in there. Some are folded in half if they are too long. When they lay straight like this, they don't get wrinkled. This is what I use to make a "Log Cabin" Freedom quilt. All sizes and colors get added, no need to be the same width, or even square. Start with a really bright small piece and built around that until you get to the size you want. Put those together with sashing, and you have something pretty.
My box is saying it's time to make another one pretty soon.
Other things have their own place. No mixing. The real "strings" - selvage cut-offs - go in a drawer and are used to tie up "stuff": fabric bundles, bag tops, tomato plants, morning glories, etc.