Hearth residue

I believe the answer is:

soot

(Other definitions for soot that I've seen before include "Carbon black" , "Chimney deposit" , "Carbon deposit from burning" , "Something stuck down the chimney" , "Black chimney powder" .)

I've seen this clue in The Mirror.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.