I'll occasionally peruse the Search & Explore tab of Instagram. Back in June, I came across an Instagram post by Naomi Bulger, a snail mailer (among other things) out of Australia.
She'd made a bunch of tiny letters and was offering to send them off, so naturally, I signed up, because I cannot pass up an opportunity to receive neat snail mail.
The tissue paper used for the envelopes are from old postcard books, and separated each postcard. A canceled Australian stamp and a little handwritten haiku came inside, sealed with a drop of wax. The vellum envelope that the tissue paper envelope was mailed in also included colorful Australian postage.
I'm not a hardcore stamp collector, but over the years, I have saved interesting stamps that I came across and do have a little stash stored away. I've thought about pulling them out just to look through them and maybe take some pictures (like, say, sorted by color or themes), but that requires pulling out a bunch of things from the closet and I haven't brought myself to do that just yet.
I say that I'm not a hardcore stamp collector, but I do remember when I was younger (I think middle school?) going to the library and checking out some books about stamp collecting and flipping through them. From those books, I gathered that I shouldn't actually cut stamps out from the envelope and should actually save the entire envelope with the canceled stamp(s). I don't know if that's still true or not, but that's how I stash stamps away now is with the envelopes they came on.
The other thing that I haven't figured out is how to get self-adhesive stamps off of envelopes (unlike the old ones where you use water to activate the glue). To be fair, I haven't Googled or researched it because it hasn't been a priority, but it's crossed my mind!