Hey there!
I love Dr Browns bottles! But Omg yes they are a pain to clean. I'll tell ya what I do. It may go against the directions, but they are clean and not mildewy lol.
After he eats, I take it ALL apart and run hot water into the bottle. I use a bottle brush and clean the bottle, and the nipple with dish soap. I rinse these. I rinse the nipple ring with hot water. I take the middle tube thingy and shove the soapy bottle brush into it too. Then I take the tiny brush they give you and put dish soap on it and run it through all the holes in that tan thing, and down the center of that tube thingy. I rinse them. Then I put everything in the dishwasher. I have a nipple basket, and baskets that I put the nipple ring and the tan thingy in, and I stand the tube thingy up on the things in the dishwasher that the cups would go on, I put the bottles upside down there too. So everything in on the top rack. I have been doing this for 5 months with not one problem at all.
Hope this helps some!
Hugs,
Zoey