Pro tip: the retired sweep in Rochester who warned me about "just rodding it" from the top
Honestly, he flagged me down in a supply shop parking lot 2 years ago and said to never force a stuck brush down from the top without checking the smoke shelf first. Last month I hit a jammed flue at a 1920s colonial and sure enough, there was a fallen cap wedged right at the shelf that would've dropped straight onto a cold stove. Has anyone else run into caps coming loose like that on these older liners?