I've found ludlow backs for OS 1 and 2 at an estate sale, which was strange as I thought ludlows never made it to the west coast. Also a book of die cuts where I bought every one at a flea market, leaving the 1960s batman cards.
i don't mind quantity over quality esp if there are cards I don't already have....but I wouldn't turn down an unopened box of diecuts, ads or OS....
A