Tried the plastic sheet trick on a nasty flue last week and doubled my drop time
Had a job in Portland last Tuesday, a 1920s bungalow with so much creosote the brush was coming out black every pass. I tried taping a plastic sheet over the fireplace opening with a slit cut for the rods, which I saw some old timer mention once and never bothered with. Usually I get maybe 20 minutes of brushing before the dust drives me out, but with that sheet up I stayed in there almost 45 minutes and the dust barely touched my respirator. I pulled down close to two gallons of soot, which is double what I'd get on a normal first pass. Anyone else run a sheet or a cardboard box rig on heavy flues, and does it mess with your visual check of the smoke shelf at all?