According to difficult child 2 - who thinks he knows everything, but does not - if you are an occasional smoker it's out of your system fairly quickly....a week or less. If you're an everyday user - like him - it stays in your system longer, but he supposedly passed a drug test recently. Don't know what he did or even if he really did because I haven't talked to him since.
I would not use bleach because they will be able to tell that the sample was messed with.