Apply chemical creosote treatment (modifiers/removers) on glazed third-degree creosote that mechanical sweeping alone cannot remove

Steps

1. Confirm via inspection that the creosote is genuinely glazed/third-degree (hard, shiny, resistant to brushing) before committing to chemical treatment, since lighter creosote should be handled mechanically
2. Select a creosote modifier/remover product rated for the flue material in use (masonry tile vs. metal liner) and follow the manufacturer's label directions exactly for dosage and dwell time
3. Apply the product per label instructions, which typically involves introducing it via the firebox or top-down and allowing repeated appliance burns or dwell cycles to chemically break down the glaze
4. Follow up with mechanical sweeping after the chemical dwell period, since most products are designed to soften/friable-ize the glaze for mechanical removal rather than dissolve it outright
5. Re-inspect with a camera to confirm the glaze has been sufficiently broken down; repeat treatment cycles if third-degree creosote persists
6. Advise the customer on burn practices (seasoned wood, adequate draft) that reduce recurrence of glazed creosote