Well I was out on the roof is weekend putting up x-mas lights and I noticed black powder on the chimney cap so I went out and picked up a 6" wire brush to clean the liner as soon as the weather breaks. My thing is the steel wires on the brush seem to be very stiff. Will this ruin or put holes in the stainless liner.I now that stainless can handle the heat but it is a really soft metal and I don't want to run this brush down my liner if it going to ruin my liner. I think that I read on here that there is a poly brush is that for stainless liners. I would like to now if I have the right brush or do I get the poly brush Witch one it the best one for the liner poly or wire?