i heard before that going in propal sauna(steam saun)will speed thing up a big time..i dont have any facts or anithing to back me up,but you should take a wee look at that.
i know tht if your been drinking and your alchohol level is 1.7mg and you spend 30 min in sauna with 75c youl alchohol level will drop down to 0.2-0.4mg(averege size teenager)
it might work with weed as well=)