Do you re-use unfinished bottles of breastmilk? Let's say I put 4 oz in a bottle and she only takes 2 oz. Do you refrigerate the rest and re-use it, or do you throw it away? How soon do I have to feed her the rest before it starts to go bad? I feel terrible about throwing it away, but LO hates the bottle and it is a fight to get her to drink it. I should probably just do 2 oz at a time going forward so I don't waste any, but I am always optimistic that she will drink 4 oz in one feeding (which she has done only once before).