I am not sure how to file this yet. As a Minneapolis cancel on postage due, in my postal markings under Postage Due or Pointing Hand . . . so many choices.
Was the postage due because it was stamped "First Class" (in Tijuana probably)? I'll take my answer off the air.
re: Mexico to Minneapolis - Postage Due - 03/11/43
Nothing on the back except notes written by the recipient about random stuff. I think the cancel on the postage due stamps would have sufficed for the received cancel.
I think at first they were going to return the cover, then they figured out she lived on 108 12th Street Apt 2 (rather than 108 8th St). Otherwise the postage due would have been collected in Mexico by the sender when they got the cover back I think?
re: Mexico to Minneapolis - Postage Due - 03/11/43
Let us know what you decide on filing this. I have a box of "where to files?" and other covers that I've filed one way and then when I "run across" that cover I wonder "why in the world is that here?" Indecision is a terrible thing.