Any of you guys clean your chimney with a container of ammonia at the base of your chimney? A guy I work with says he does it and it cleans all the creosote right out without any physical work. I'm skeptical but may try it
Ammonia has alkaline properties - I'd be worried about corrosion in a metal lined flue. I'll stick with the brush.
Ammonia should react with the acidic creosote so maybe it would do some good. Who knows until you try it.