I've found that a great long term solution to storing stacks of invoices and such is wrapping them in kitchen film. Take a 4" stack of paper and wrap it in serene wrap, press the air out before you make that last seal, and that 4" stack of papers is now a 1" tightly wrapped neat bundle! I sometimes make a "label" top page before wrapping, to ID the stack, but even if you don't, heck, it's clear. You can tell what's in it pretty much. Plus, the bundle is now water and air resistant. Will it float? I don't know. I do know that it takes up a lot less space, and it will definitely stay fresh. Now I can just chuck 'em up into the attic, knowing that if I would ever need them (over the course of the 7 yrs I'll store them) they're in top condition.