im not sur ehow you an get it out of your mouth. i dont even think you can do it in a speedy mannor in all honesty but im not a scientist.
when you do a piss test, you can flush out your bladder so the THC isnt in your piss anymore, i know you can do this buydrinking a HELL OF ALOT OF WATER the week before or a couple days before.
god knows how your gnna clean out your saliva try spitting all day lol.