I have a 6 1/2" x 6 1/2" clay tile chimney 25' tall. I have run a brush through and it is mostly open except for a 5' section in the middle. Can't really tell if it is just creosote or also sloppy mortar joints. I was able to pull a 12" long 6" diameter section of black pipe through so I know I can get the 6" stainless liner all the way through but am concerned about the insulation. Definitely no way to pull a liner with insulation wrap so will have to use the vermiculite insulation mix. Problem is that I don't think I will be able to shake it down because of the restriction in the middle. I ran a flashlight down with some string and can see there is lots of creosote in the corners. If I could clear out the corners, I think the insulation mix will fall through. What I really would like to do is get a chisel and pound away in the corners. Any ideas on how to make a chimney scraper that will do the trick? Any advice for getting the insulation mix past restrictions like this?