跳进黄河也洗不清

跳进黄河也洗不清

Literally means:

be unable to cleanse oneself even if one plunges into the Yellow River

Actually means:

find it hard to clear oneself of a charge; it is impossible to prove oneself innocent

黄河 refers to the Yellow River in China.

The phrase figuratively means being unable to convince others of his innocence. It is often used to indicate that someone cannot prove that he is not to blame for something and should not be indicted, suspected or wronged.

黄河，中国的一条河流。

跳进黄河也洗不清，比喻无法使人相信自己是无辜的或清白的。常用来指一个人不能证明自己对某件事情没有任何责任，不应受到指控 嫌犯或冤屈。