I am trying to remember/find a book about a little girl who doesn’t have much, except her little treasures. I think it was a stick of chewing gum, a jack ball, and a few other small items. She lives in a brownstone and it seems like she hides her treasures behind a brick. She takes them out and looks at them often. The front of the cover had her and another person sitting on concrete steps with a railing. I don’t know if it was a little golden book or not. It seems like it was about 5X5 square, about 10 pages? I would have had it read to me around 1970ish. I can’t remember much else. I have looked everywhere for it, only being able to search by the memory of the cover.