Great find01/19/2013 ByAmber M. After a while the Medela collars crack at the top. I always hand wash them as well so I think it has to do with the bottle warmer. I was happy to see that there was a replacement kit for bottle parts without having to buy a whole other set of bottles. Mommy Gear has the best prices and selection on all their pumps and accessories. This is my third child and third Medela pump so I have done plenty of research.