By Daniel Watkins, Noble Chimney Sweepers.
A fireplace looks like it will take anything that burns, which is exactly why so much gets fed into one. Working through our Lemont chimney service area, the flues in the worst shape are rarely the ones that get used the most — they are the ones that got used as a disposal. Here is the list of things that do not belong in a residential fireplace, and the specific reason for each, because “don’t burn that” without a reason never sticks.
Treated, painted, and manufactured wood
Never burn pressure-treated lumber, painted or stained wood, plywood, OSB, particleboard, or MDF. These carry chemical preservatives, finishes, and adhesives that were never meant to be combusted in an appliance vented into a house, and the residue they leave behind coats the flue.
Pressure-treated deck scraps are the most common offender because they show up in a pile after a project and look like firewood. They are not firewood. Old fence sections, torn-out trim, and construction cutoffs belong in a dumpster.
Driftwood and salt-exposed wood
Salt-laden wood releases corrosive compounds as it burns that attack metal components — liners, caps, dampers, and connectors. It is a fast way to shorten the life of hardware that is otherwise doing fine.
Wrapping paper, cardboard, and junk mail
These burn hot, fast, and light, and that combination is the problem. Glossy and coated papers carry inks and coatings you do not want in the flue, and large sheets of paper produce burning fragments that ride the draft straight up the chimney and out the top.
The holiday version of this — a heap of wrapping paper on the fire the morning it comes off the presents — is a genuine seasonal cause of chimney fires and roof-ember scares. If your flue already has creosote in it, a sudden hot flare is precisely the ignition event that layer has been waiting for.
Green and unseasoned wood
Wet wood spends its energy boiling off water instead of producing heat, so it burns cool and smoky — the ideal conditions for creosote to condense on the flue walls. It is not dangerous in the moment; it is dangerous cumulatively, one lazy fire at a time.
Christmas trees and yard waste
A dried conifer, leaves, or brush will flash into a violent, sparking fire that is completely out of proportion to the amount of material. Yard waste also often carries moisture and dirt, which produce smoke rather than heat. A discarded tree is a bonfire hazard indoors, not a convenient log.
Accelerants and charcoal
Never use gasoline, kerosene, lighter fluid, or any other accelerant to start or revive a fire in a fireplace. The failure mode is immediate and it is not recoverable once it starts.
Charcoal deserves its own line for a different reason: it produces heavy carbon monoxide and is meant for open-air use. It has no place in an indoor fireplace, and neither do coal products in an appliance not built for them.
Plastics, foam, and household trash
Plastic, foam packaging, food wrappers, and diapers release harsh compounds and leave sticky deposits in the flue. There is no version of this that is fine in small amounts. A fireplace vents into the air your neighbors and your own upstairs windows share.
So what should you burn?
Seasoned hardwood, split and dried until it has lost most of its moisture, plus plain kindling and unprinted paper to start it. That is the whole list. Manufactured logs are acceptable if you follow the wrapper and burn one at a time, but they are formulated for open fireplaces and are not a substitute for cordwood in every appliance.
The other half of clean burning is a flue that starts the season clean. If the last few years included any of the items above, assume there is deposit in there and get a chimney sweeping before the first real cold snap — and if you ever had a flare-up you are unsure about, ask for a chimney inspection instead, because heat damage does not clean out.
Where we fit in
We will tell you honestly what your flue looks like, and the price is given up front before we start — our rates are on the pricing page. Between visits, our DIY chimney maintenance page covers what a homeowner can safely check without going on the roof.
Noble Chimney Sweepers is certified, bonded and insured, and owner-operated. I have been sweeping chimneys for 14 years, and we answer 7 days a week, 7 AM to 7 PM, at (708) 432-5747.
Frequently asked questions
Is it really that bad to burn a little cardboard?
Yes, avoid it. Cardboard burns hot and light enough to send burning pieces up the flue, and coated or printed stock adds residue. The amount does not change the mechanism, only how often you run the risk.
Can I burn pine or other softwood at all?
Properly seasoned softwood can be burned, and it is useful for kindling. The caution is that softwood carries more resin and dries differently than hardwood, so unseasoned softwood produces creosote quickly. Dryness matters more than species.
What about pallets?
Do not assume they are safe. Pallets may be chemically treated, painted, or contaminated by whatever they carried, and the nails and staples left in the firebox are their own nuisance. Unless you know the pallet is untreated heat-treated wood, keep it out.
Are manufactured fire logs safe in my fireplace?
Generally yes in an open fireplace, following the packaging, and one at a time. Do not add wood to a burning manufactured log, do not poke or break one apart, and do not assume they are correct for every appliance — check what your unit is rated for.
Someone told me burning aluminum cans cleans the chimney. True?
No. There is no household item you can burn that safely removes creosote from a flue. Deposits come out mechanically, with brushes, by someone who then looks at what is underneath them.
I burned wrapping paper last winter. What should I do now?
Have the flue looked at before the next burning season. One hot flare does not guarantee damage, but it is exactly the event that ignites an existing creosote layer or shocks clay tile, and both are invisible from the firebox.
Does an air purifier or a screen make bad fuel acceptable?
No. A screen catches embers in the room and does nothing about what travels up the flue or what condenses on its walls. The fuel is the variable that matters.
How often should a regularly used fireplace be swept?
It depends on how much you burn and what you burn, which is why an annual look is the standard advice rather than a fixed interval. We serve Lemont 7 days a week and can tell you what your own usage calls for — the full list of what we do is on our services page.
Published September 18, 2026