Some of you may already know of these things - if I had known about them before I traded my NPS plaques for chips, I may not have done the trade - but I came across something unexpected when I went looking for some sheet protectors in our office supply stock. They're baseball card holders from a company called "C-Line Products" (not-affiliated disclaimer goes here), and they may just work for storing a collection of plaques.
Here's the details, for those who are interested:
-10 holders per package
-Top-loading polypropylene pages for 2.5" x 3.5" cards (are plaques larger than that? Not sure)
-9 slots; 3-hole punched sheets
-And here's the kicker: archival quality, acid-free protection (unlike the chip binder sheets I just purchased).
I Googled them (listed at
http://www.c-lineproducts.com/SpecialtyHolders.html under "Collector's Edition Holders") to see if they had archival chip sheets; they don't, but I might call them to see if they could do the 2.5"x2.5" needed for my flips. In any case, I have an open pack of 6 of these available for free (shipped in the US) for anyone who wants them. The first person who owns plaques and PMs me their address, gets them.