Warning: the $30 brush set I bought at a supply house in Cleveland scratched two liners, so now I only run poly
Every old timer in my area swears wire brushes are the only thing that actually scours a flue, but after I pulled a 6 inch round wire brush through a stainless liner last month and watched it leave bright scratch marks the whole way down, I switched to poly and my rods come back clean with no metal glitter in the dust pan, so what are you all running on stainless, wire or poly?
Same exact thing happened to me with a wire brush on a stainless liner, scratched it all to hell and the homeowner was not happy. Poly all day now, way cheaper than eating the cost of a new liner.