I am down here in Panama and when someone request a QSL card, they usually put money in it to cover the cost of postage. On two different occasions, I have rec $2.00 bills. I have them taped to my computer here in the "shack". I often wonder what the clerk would do if I tried to "pass" them! As I am not fluent in Spanish, I would have a hard time trying to explain my way out of the situation.