If you peer inside a used catalytic converter, nothing looks salvageable, much less valuable. But some of the gray gunk in there hides three expensive precious metals.

• 如果你仔细看看用过的触媒转换器里面，似乎没有什么可以回收利用，也不值钱。其实里面的一些灰色的泥状物中就藏着三种昂贵的稀有金属。