Bottle brush in a cordless drill. Every bottle, every time.
If I threw out every bottle that got moldy , I'd have to drink through a straw into the carboy... no portability that way.
So far, I've had more experience thinking than I've had brewing....you don't think they are mutually exclusive, do you?
57 batches so far,
33 wine, mostly Loquat, peach, plum, prickly pear
22 beers and ciders
1 Tequila, from a prickly pear wine experiment that didn't work. I call it "Prickly Heat"