What's Spanish for "Shut the hell up because you already know I don't speak Spanish"?

A guy came into the store yesterday asking if anyone there spoke Spanish. After repeating "No hablemos Español" to him several times to no avail, I finally realized that the reason for our apparent miscommunication wasn't the language barrier. It was the fact that he was retarded. He continued to ask if anyone spoke Spanish, and then he pointed out his wallet full of US dollars. Evidently, either he was trying to show me that he wasn't planning on paying in pesos, or he was asking me to take his money and poke him in the eye. Anyway, long story short, I can't get the smell of vitreous humor off my hands.