A couple days ago I pulled the double wall stove pipe apart to straighten up one of the connections and noticed alot of what looks like flaky ash about 1/8in deep. I have only been burning this stove [hearthstone homestead] for 3 weeks. Does this sound like a problem, we have been burning mostly pine, the chimmny looks fairly clean, light ash etc. Also how much creosote or ash should be allowed to build up before cleaning, oh yeah the double wall is about 4 feet long than a 45,a 6in. section than another 45 that connects to the ceiling support box. The chimmney is 10 feet of 6in. class A in an enclosed chase open at the top?