How to maintain an old brick wall

Question

we have a small section of exposed brick from an old chimney in the kitchen. The chimney is now used as an exhaust for the furnaces in the basement (and maybe for the kitchen exhaust in a different apartment). How can we clean and maintain the brick? Here are the two things I am concerned about:

• Sooting? I am not sure what the correct term is in English. It's called "Versottung" in German and I am wondering about the black areas in the pictures.
• Crumbling particularly of the mortar. One of the pictures shows a little hole and mortar certain comes off when I scrub it (see residue in one pic). In some limited areas, that happens a lot.

So how do we address these issues and maintain the brick wall. We might want to cover it at some point but it might also remain exposed.

Answer 1

Soot sounds good to me . To have localized areas outside the flue (where the smoke goes up) is bad news. The loose mortar needs to be removed and the mortar repointed (new mortar pressed into the cracks and the joints filled).

Once you have the crumbling mortar removed and repaired with fresh mortar you should not have any more soot getting out. Trisodium phosphate is a good cleaner that will take the soot off with only a little elbow grease. Let us know how it turns out.