I hear drinking a lot of vinegar (nasty, i know), and taking a good piss afterwards significantly reduces the amount of thc in the blood. or maybe it's not that. maybe you're supposed to pee the vinegar into the test cup and the weed doesn't show up. also, i hear that if you sneak in a little salt in your pocket the day of the test, you can dissolve it in your piss and it comes out clean. not sure if any of this works, though, since i've never tried it. the shrooms shouldn't show up on the test if you haven't used them for over a week.
But the hell with the salt and the vinegar. if you can get your hands on about fourty dollars and go to GNC, they'll sell you a substance that rids your blood of thc in 48 hours. Ask about it openly, tell them you're taking a drug test. they're used to hearing that kind of thing. If you don't live in the us or don't have a GNC closeby, then i really don't know what you can do to get your hands on this substance, but you should definitely try. it works; i have more than five friends that have used it successfully.