跳到黄河洗不清/ 跳到黃河洗不清tiàodàohuánghéxǐbuqīng(also tiàodàohuánghéxǐbùqīng)to be unable to clear one's name
Literally meaning that one cannot wash clean even by jumping into the Yellow River; used to describe being unable to clear oneself of a false charge or a bad reputation.