Well that time off year, I have a SS flex liner and after the first season I need to do what I probable should have done at least once last season but never got to it. My question is poly or metal brush to sweep the liner. From what I read, I should use poly on the flex liner but I then read that poly brushes will not remove creosote.They only remove soot, So not wanting to damage the liner do I use the poly with a chemical spray or go with the metal brush and just go easy. P.S. Hope all had a great summer