" You know. I never really thought to ask before—but what is that dust made of?” “Depleted uranium,” I told him. “At least, that’s the base ingredient. I had to add in a lot of other things. Cold iron, basil, dung from a—” “Never mind,” he said. “I don’t want to know. "

― Jim Butcher , Grave Peril (The Dresden Files, #3)