I am collecting bottles for my first batch of home brew. Some that I haven't returned and some that my local packy owner is saving for me. They are all bombers. The problem I am having is with the ones I'm getting from the local packy. Many of them have lots of mold in the bottom and they are hard to clean. I am using a bottle brush from a five gallon home brew kit and dish soap. All bottles are dark and it is hard to see if I got everything out. Does anyone have any suggestions on better cleaning methods and how to keep them from collecting mold prior to bottling. I know I have to sanitize them before bottling but I don't want to have to clean them all again.