Shoutout to the old-timer who told me to stop using wire brushes on clay flues
I always thought a stiff wire brush was the way to go. Get in there, scrub hard, get it clean. Last spring I was working on a house built in the 1920s. The clay liner had these hairline cracks I never noticed before. The homeowner's dad was a sweep back in the 70s. He came out, looked at my gear, and told me I was grinding the glaze right off the tiles. Said that glaze is what protects the clay from soaking up creosote and moisture. I watched him demo a piece of old clay with just a poly brush and a shop vac. Night and day difference. The glaze was still smooth, no scratches. Now I only use poly or nylon on clay. Has anyone else seen that kind of damage from wire brushes on older liners?