"I'm afraid I don't know what an American dollar is, but I have something that should work." He fishes out a couple of silver coins from his pocket, offering them to Schön. "The coins are all silver, but I'm afraid I don't know what that means for your exchange rate. And just one for now, thanks. If it's good, I'll come back for more."
I don't know, but I feel sorry for those that don't!