How do I clean the inside walls of a firebox?

Wood firebox: brush first, then scrub

Start cold and cleared of ash. A dry, stiff brush knocks most soot right off the firebrick, which is the easiest and safest first pass. For baked-on soot or creosote, use a firebox or masonry cleaner — or a paste of water and a mild abrasive — with some elbow grease, then wipe with a barely damp sponge.

The one caution: don't soak firebrick. It's porous and holds water, and saturated brick can spall or crack when you fire it back up. Let it dry fully before the next fire. A little white powdery residue afterward is efflorescence — mineral salts — and brushes off.

Gas firebox: hands off the hardware

A gas unit is a different animal. The 'walls' are usually painted steel or a refractory liner made to look like brick, with logs and embers arranged just so. Gas off and cold, use a soft brush or gentle vacuum for dust only. Don't scrub it, don't wet it, and don't move the logs or touch the pilot and burner.

Heavy soot inside a gas box isn't a cleaning problem — it usually signals a combustion issue, like logs out of position or the wrong fuel setup. That's a service call, not a scrub brush.

When the walls themselves are the issue

Cracked firebrick, crumbling refractory panels, or soot that keeps returning no matter how you clean point to repair, not cleaning. Cracked panels get replaced on a schedule, and persistent sooting gets diagnosed. We inspect and service all major brands and can tell you which it is. Call (828) 545-0525.