A clean chimney effectively sucks out harmful gases from your fireplace WHILE it is in use.
Regular sweeping will remove soot, bird nests, cobwebs and any other blockages. It also
removes creosote, which will help to prevent dangerous chimney fires. The good folks at A
Noble Sweep, a Louisiana based chimney cleaning company, says to call for a chimney
cleaning if you see any of these 8 signs!
https://anoblesweep.com/signs-you-need-chimney-cleaning-services/