I have had the exact same problem with my Aluball pro. Mine is black, as well. I just take it easy when shaking now. Instead of shaking it agressive, I just shake lighter, but for longer, and I try to keep the ball from smacking the lid. One thing i've heard of others doing it using uhh, saran wrap? Is that how you even spell it? To cover the lid. Basically you just put it over the bottle, then screw the lid on. Use a few layers of it, it should still screw on, and it'll prevent your ball from hitting the lid. Not only that, this also protects the ball and increases life-span. But yeah, definitely had the same problem. Lost a few batches of Kava due to this. At first I didn't realize what it was, thought maybe my ball broke and bits of root were coming out but.. then I realized and noticed the lid when cleaning it later. Helps if you take a paper towel to the lid or something and scrape off some of the loose bits before your next shake.