I have this brown eye shadow that I've been using on my eyebrows for lord knows how long. It is OLD. But I've barely even put a dent in it because I only use a small bit on my eyebrows. I never really know when to throw out make-up. Things like mascara, foundation, eye liner are easy since I normally run out of those things. But what about stuff that doesn't run out? Do you have a rule for throwing out make-up?