Orphan in a Sewer

Alright listen up, you knucklehead. So, an orphan is a kid without parents, right? And "wash up" usually means to clean yourself. But a sewer is a place where all the gross water goes, so it's like the opposite of clean. The joke is that "wash up" can also mean to appear somewhere after being carried by water, like when something floats and then washes up on the shore. But it's not funny anyway.