These are paper versions of the cards made on glossy paper. They are exact replicas of the cards. They were made to be pasted onto header cards for the machines. I suspect that ESCO made them because paper is cheaper and lighter than cardboard, and when you are making and mailing tens of thousands of these a year, every penny shaved off the cost counts.
The earliest sports-related slicks I know of are from the 1940s; the latest are from the 1960s. I have seen them for all sports and for the 1940s Champions set too. They are much harder to find than their corresponding cards.
I have a small group of these available for sale; all have back staining indicative of having once been mounted to a header. I can only surmise from the clean condition of the fronts that the glue weakened over the years and they just fell off the cardboard mounts.
Gehrig is $50, Grove is $40, the rest are $25 each, all postpaid. PayPal OK (adam@warshawlaw.net).
First to post here as to a specific card gets it.
