Yeah, this one’s tough.. I ended up finding an old water bottle and I’ve been using that until I can find a more permanent home for my no-poo concoction. Your best bet is to use a bottle that contained something relatively safe to begin with.. maybe shampoo/conditioner, oil (almond, coconut, etc), natural hand soap or lotion. That way, if you don’t get it completely clean—and you most likely won’t—it’s okay!