I have the Medela PIS that I have been using for about 6 months. I pump when away from dd. My question is is that for the past few weeks I have been having a hard time cleaning the attachment that connects the sheild to the bottle(not sure what it's called). Especially one side is getting molding right in the middle where nothing that I have for cleaning will fit.I have used a bottle brush the small side, I have used a tooth pick, I boiled them yesterday for what seemed like forever and I have even tried the dishwasher and nothing works efficiently. Any tips? Much appreciated!!