Does anyone know the real shelf life of open eliquid? I found a bunch of bottles of old liquid in a drawer today. I had used them a little bit and then put them away. Most of the bottles are almost full. Most of them also expired in 2012-2013. Are they safe to vape? Would it be dangerous to use them? Do they lose potency with age? I don't want to just throw them out if i don't have to.