Guy at the supply house said to skip the drill on clay flues, cost me a callback
A guy named Ray at the supply house in Albany told me to run the poly brush by hand on old clay flues instead of using my drill, said the drill cracks tiles. I listened to him for about 3 jobs, then a homeowner in Schenectady called back saying her flue was still caked with creosote at the top. Now I use low speed on the drill and haven't cracked anything in 6 months, so was Ray just being extra careful or was he flat out wrong?