i loooove those little bottles!! i use them to store milk in the fridge and when we go out i just drop them in the diaper bag with a nipple/collar/cap and we are good to go, the rest of the milk goes to bags for freezing.
we wash them with hot soapy water and then i sterilize them BEFORE putting the freshly pump milk in... works for me and like i said i love them, we just couldn't live w/o them!! my lil girl will sometimes take 2 oz and some other times will drink 5oz so these work perfectly for me, she either gets 1 or 2 bottles per feeding :D
Hope this helped