I've had mine in binders for a few years, and put extra ANS cards flipped behind the stickers I wanted to keep from curling. Ended up putting them rings-up, pages-down (i.e. horizontally pointing down) in a file drawer, which keeps the pages "hanging".
Am thinking of going the toploader binder route one of these days for the keeper vintage sets. That's one of the advantages of the reprints and ANS stickers - the hard backs - so at least I don't feel the need to do this with more than the vintage stickers!