Sammy’s Bowery Follies was not the first “dive bar” nor did they invent the idea of “slumming” but for a stretch of time through the 1940s to the 1960s, Sammy’s was New York’s best example of both.
The exponential growth of a postcard collection creates problems of organization. How to keep cards of similar nature together is a problem we all experience. We have no answer for you but learning that you have a problem is half the fun.