My house that we purchase 3 years ago was built in 1978. When we bought the house, the original fireplace had a cast-iron insert which was very ugly and had a very small fire box. My wife and I hated it and since our new furnace heats the house just fine and energy efficiency wasn't a concern, I removed the insert along with its chimney liner. I later had a chimney sweep out to inspect the situation and he determined that I needed a flue re-line (he wanted to replace the original terra-cotta clay sections with the same) and that my smoke chamber and firebox needed repairs. I decided to go with a flexible stainless reliner and I'm fairly comfortable with the installation steps that I need to do there but my questions are now around the smoke chamber and firebox. I'm pretty sure that there was a chimney fire a some point since the flue is cracked pretty severly in several places and the amount of creosote and ash I found in the smoke chamber. My question is this, does something need to be done along the lines of re-parging my smoke chamber? If you look at these pictures, you can see some clumpy deposits still clinging to the smoke chamber wall. I tried scraping these off with a putty knife but they're on there pretty good. I could break out the cold chisel but I'm afraid that I would distrube the masonry if I do that. Should I just leave it alone? You'll see in the picture that the top 5 back rows of fire brick for the smoke chamber along with the smoke shelf were removed by some previous owner so I need to re-build that but my question there is, what exactly do I finish the smoke shelf with? Should I just finish it smooth with standard brick mortar or do I need to use refractive mortar? You can see at the back of the firebox where the bricks have been removed It's a little blurry but you should be able to make-out the lummpy stuff that's on the smoke chamber walls in this photo This is the back of the firebox and smoke self area that needs repair Another Angle Thanks for any help!