I prevented this problem by only using atties for darker juices like Cinnamon Bun. The cartos I use for the clear ones. After refilling too many times to count they're still going strong. The atties need cleaning quite often. Your post has piqued my curiosity now and when I order more cartos I'm going to try one with dark juices to see how long one will last before needing cleaning. Thank you for the heads up on the PhilB video, Queenie.