I had a pretty much dead 901 atmoizer. It gave me very little vapor even when dripping. Anyway I had it hooked up via passthru and decided to play around with it. I covered the atomizer hole with my finger and decided to pull long draws on it 3 to 4 times. It smelled burnt and tasted disgusting so then I put it down. I came back about an hour later, dripped it and popped in a new cart and I coughed from the unexpected throat hit. It was working like new again! I'm still in the process of breaking in my new m401 so it was a huge pleasure getting throat hit again. Maybe there is a reason for the "cleaning cycle." So if anyone's got a dead atomizer, maybe this will help you! Happy vaping! 