Swept my chimney yesterday. I got 6 cups of powder (first time I've actually measured it). I see all these posts of 24/7 burning for 6 months and getting a thimble full, so I'm not sure if this is anything to be concerned about. I have a 25 ft insulated liner. I burn HOT, and a mix of dry wood and liberty bricks. This is after 1-1.5 cords last season. Don't think the wood is the problem, don't think my burning habits are the problem. Only thing is that with the 602, I have frequent cold starts. Thinking this is probably more likely to lead to build up than a constantly hot stove?