To quote the late Paul Harvey:
"And now... the rest of the story..."A few weeks ago I was doing my normal browsing of U.S. revenue lots on
ebay, and as I scrolled through images on one particular listing, I passed all of the revenue material and the images proceeded into the "other" portion of the lot, and by that point I had decided the lot wasn't really worth my time. I was just about to close the browser window when I saw some images that made me go:

While I do only collect/specialize/focus in certain specific areas, at my core I subscribe to notion that if you see something odd, interesting, unusual, scarce, or aesthetically pleasing, you'll likely never go wrong acquiring it (financial limitations notwithstanding).
I started looking at current and completed
ebay listings, Hipstamp, Stamp Auction Network archives, auction catalogs, and could not find a single comparable example. Maybe they're just so low of a value that they wouldn't ever be offered individually, hence there not being records of similar items, but dang it, they sure look unusual to me.
So I placed my high bid and waited. I ended up winning the lot for far less than my max, so either I was mistaken in the appeal of what I saw, and it wasn't of enough interest/demand/scarcity for others to bid higher, or... given the way, the lot was categorized and titled, the people that WOULD be interested just didn't know it was available.
I have seen a myriad of follow sheets/postage due bills/top-of-stack sheets (whatever term you choose to use) over the years, but they almost universally fall into one of the following categories:
1. Sheets with exclusive postage due stamps affixed
2. Sheets with exclusively postage stamps affixed, most commonly leading up to or after the phaseout of postage due stamps in 1986. Yes, I've seen examples of earlier sheets with postage stamps affixed (like some of the examples shown in previous posts in this thread), but they tend to be the exception rather than the rule.
What I had never seen before were follow sheets with OTHER types of back-of-book stamps or a mixture of different stamp types wallpapering them. That's what jumped off the screen to me.
These follow sheets are all from the same post office, dated 1952, so well before the phaseout of postage due stamps. They are INCREDIBLY brittle and fragile. I had to remove the staples and stabilize the documents with archival mending tape as best I could... even so, I wound up with edge chips all over the damned place.
Some are incomplete. I'm showing them in chronological order.
I don't know if they ran out of postage due stamps and were just using what they had available, but given the mix of both postage due and non-postage due stamps on individual transactions over a period of time, I can't help but wonder if this was some sort of attempt at accounting for the types of services provided (special delivery vs. special handling vs. normal delivery?). I'd really love to know what the thought process was.
I'd love if they were in better condition, but beggars can't be choosers... I've never seen anything like them before.
