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Should you use nifty gadgets to clean your chimney?

House Doctor | Gary Dymski

December 22, 2005

I recently used one of those cylindrical cleaning sticks designed to clean soot and creosote from my oil-burning furnace and chimney. Is there any danger in using such a product? Is it a health risk? Can it harm the boiler or masonry in the fireplace?
Ben Lampert, Queens

Over the years, I've come across dozens of miracle additives that are supposed to clean, refurbish and renew everything from septic tanks to fireplaces. Most of the time, such miracle cures are a waste of money. I'm afraid your cleaning stick falls into that category.

When researching information about cleaning and maintaining chimneys, one of my first sources is WoodHeat.org, run by John Gulland, a wood-burning consultant whose clients include training associations and the Canadian government. That's where I headed with your question.

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At the site, the Wood Energy Technical Training reference manual, a part of the Canadian training and certification system for wood heat technicians and inspectors, says many of these so-called "soot-cleaning" sticks are made from chloride-based powders that also contain copper, zinc and other metals. While they are the oldest chimney chemicals, these metals have corrosive properties, especially to steel and cast iron.

The manual says these powders are effective only at high temperatures, so they must be used with intense heat. Burning these sticks with wood can form toxic materials. I'd avoid these sticks and clean the old-fashioned way: with stuff brushes and cleaning solutions designed to break down the crusty creosote.

If you want great information on maintaining your chimney and removing soot and creosote, visit WoodHeat.org.

By the way, if you think a chemical treatment is the way to go for your fireplace, Gulland recommends manganese-based liquids. Be sure to follow the manufacturer's directions.