Talk about storage methods that no longer exist. One that I rarely see are square window 2x2s. Instead of the cardboard cutout being round, they were square.
I suspect those were for photo slides for use in slide projectors, that were repurposed to hold coins.
My favorite Roonyism: If a vacuum cleaner sucks, does that make it bad? As far as old holders go, I'm looking into storing my coins in a "coin cabinet" one of these days in the near future, ideally with trays that have a maroon velvet liner....and the toning from leather pouches seems interesting as well! I really enjoy the history of coins and if I can begin storing them as collectors did back then, that would be icing on the cake.