1961 Post on Paper, Not Cardboard?
 

We found this in the three for a dollar bin at a card shop. It's not on cardboard - it's on thin paper. Were there advertisements that would have had whole cards? It could be a Xerox but it doesn't really look like a copy.

Do you have any ideas what this is?

https://www.net54baseball.com/attach...1&d=1625777929
https://www.net54baseball.com/attach...1&d=1625777929


Always looking for 1956 Topps salesman samples, miscuts, overprints, wrong back, panels, printer defects and other oddities. Also in the market for a low-grade Clemente rookie card.

Could it just be the top printed layer that was glued to the cardboard? So basically an original card skinned off the back.

Was exposed to moisture or humidity and separated from the cardboard stock.

Yes. It has happened with a few of my Post cards

I just glued it back to the cardboard

Thanks for the replies!