I have a theory that if you can piss within a certain amount of time, you can pass. What I mean is, if you piss, then piss again 20min, the second sample would be clean because there wouldn't be enough metabolytes to detect it. Thats what dilution is basically, you piss more often so the metabolytes don't build up and there isn't enough to be detected. Although I don't know if a single piss would get them all out at once, or if you'd have to flush your system regularly to get it out.