I just had a flash back of something I believe my father did. If not my father then someone else from my childhood. He kept a handkerchief in the crown of his hat. I can remember going out and when the hat came off so did the hanky come out. It was placed under the hat when it was set down and I remember it being used to wipe the hat as well. For some reason i also remember a hat being draped with a hanky while sitting on it's crown.