Crossword Genius

Flue dust (4)

Ross

I believe the answer is:

soot

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

I've seen this clue in the LA Times.
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.