How can you wash/clean waterproof jackets?

Question:I seem to wreck every one I have by washing it...only to discover it has then lost it's waterproof powers! Is there a way to clean them without destroying the waterproof coating?

Answers:
i bought a rain coat in the army and thought i got a deal on it, but it was a bust cause it wasn't waterproof. what you need to do is stop buying those cheap crappy raincoats and pony up some dough for better material