I got up on the roof today to inspect the chimney for the install of a flexible liner. What I found was a clay lined chimney 7 inches. This is good because I need to install a 6 inch liner. Problem is I can see mortar pertruding out of some of the joints in they clay tile. How would I chip that stuff off? Some are 10 feet down. Also a bigger issue is about 25 inches from the top there is brick sticking out into the chimney opening that is making the opening to small to fit the liner. It appears there is 2-3 bricks in total that gradually steps down in pertruding out. I will attach an image I hope it helps. I was able to remove one of the bricks. It's got another behind it. How can I remove the rest they don't want to come out? I was thinking of a sazwall with a masonry blade.