Candle Soot: What Is It, What Causes It, and How To Get Rid of It

I noticed one day when I was burning a candle that it was starting to smoke and was leaving black marks on the side of the candle.  This has happened to me with both a pillar candle and a container candle.  I wanted to find out what I could do about it and came across these solutions.

How do you get rid of candle soot on walls?  Use a chemical sponge (dry cleaning sponge), without water, using a wiping motion rather than scrubbing.  Once the soot is removed, use water and a liquid soap or cleaning agent, such as Dawn dishwasher detergent, vinegar, or rubbing alcohol, using a dab and blot method to rinse the wall.  Dry using a clean towel.

I came up with this list of ideas to get rid of the black marks on walls and other surfaces caused by candle soot, along with these tips to prevent candle soot.  First, let’s discuss what candle soot is and what causes it before we get into talking about these cleaning and preventative methods.

What is Candle Soot?

During the burning of a candle, the melted wax is drawn up into the wick, which fuels the chemical reaction to keep the flame alive.  This chemical reaction involves the combustion of the carbon in the wax with the oxygen in the air to make carbon dioxide and water vapor, in the form of steam.

Candle soot is black smoke that is released into the air by an unclean-burning candle.  This smoke consists of unburned carbon atoms that are being released from an incomplete chemical reaction.  The unburned carbon atoms are carried up into the air by water vapor (steam) from the combustion reaction.

What Causes Candle Soot?

Candle soot is caused by incomplete combustion of the carbon in the wax with the oxygen in the air.  Normally, this chemical reaction creates carbon dioxide and water vapor in the form of steam. 

However, when this chemical reaction is altered, incomplete, or imbalanced, any unburned carbon atoms will be carried within the steam, as the water vapor (steam) rises, which appears as black smoke, known as soot. 

This could occur when the wick gets clogged or when there is an uneven distribution of the wax to the wick and flame. 

Here is a list of various factors that may contribute to this release of excess carbon, or candle soot:

1 – The Additives Added to the Wax

  • Candle sooting occurs most commonly when too much fragrances or other additives are added to the wax, which affects the combustion (chemical reaction) of the candle. 
  • According to the National Candle Association (NCA), “the oils found in certain fragrances may slightly increase the small amount of soot produced by a candle, but wick length and flame disturbance are the primary factors that impact sooting in a properly-formulated candle.”
  • This was taken from the FAQ page of the NCA website:

2 – Flame Flicker

  • Another cause of candle soot could be flame flicker. 
  • When the flame starts to flicker, the amount of wax being used in that moment changes. 
  • When there is too much wax for the wick/flame to consume, there is an incomplete combustion of the carbon with the oxygen. 
  • This inconsistency will release uneven or unequal amounts of carbon into the air, which comes out as the black smokey soot.

3 – Lack of Oxygen/Air Flow

  • Container candles, especially glass jar candles, may produce candle soot when the candle starts to get closer to the bottom. 
  • The closer to the bottom the flame is, the less access to oxygen it has. 
  • This will cause the flame to change in size, which alters the fuel rate (flow of liquid wax up the wick) and will cause unburned carbon atoms to be released as soot.

4 – Clogged Wick

  • Too many additives in the wick can cause the wick to become clogged, which will prevent the wax from being absorbed at a constant and steady rate up into the wick. 
  • This can lead to mushrooming and change/alter the chemical reaction (combustion), which will release the unburned carbon atoms.
  • If you’re interested in learning more about mushrooming, I wrote an article all about what a mushrooming wick is and how to fix/prevent it.

5 – Wrong Wick Size

  • If the wick is too big or too small, again the chemical reaction will be off-balance and when too much carbon is produced, it will be released as black smokey soot.
  • If you want to learn more about how to pick the right wick size when making your candles, I wrote a couple articles about wick choice factors and how to make your own wicks.

6 – Type of Wick

  • Although all wicks have the ability to soot, some wicks are more prone to throwing out black smoke than others.
  • Zinc-core wicks tend to soot.  Cotton-core wicks are less prone to sooting.

Common Questions or Myths About Candles and Soot

There are many myths out there about candles and candle soot.  I wanted to answer some questions that tend to arise when talking about burning candles and the production of candle soot.  The first 4 questions, or myths, I wanted to address come from the National Candle Association (NCA).

MYTH #1:  Candles are unhealthy.

  • Are candles unhealthy?  Candles are not unhealthy and do not pose any health risks.  According to the National Candle Association (NCA), “there are no known health hazards associated with scented candles.”  They further state, “any well-made and properly burned candle will burn cleanly and safely.” 
  • Therefore, I think this reiterates the point that as long as a candle is made and burned properly, it should burn clean and there should be no candle soot released from the candle.  This is according to the NCA’s “4 Common Candle Myths Debunked” post found on their website at
  • The NCA states, “When you light a candle, the heat of the flame melts the wax near the wick. This melted or liquid wax is then drawn up into the wick by capillary action. The flame’s heat vaporizes the liquid wax to produce water vapor and carbon dioxide (the same byproducts that humans produce when exhaling).”  This quote is taken from the FAQ page of the NCA website:

MYTH #2:  Candle soot is harmful.

  • Is candle soot harmful?  The small amount of candle soot produced by an unclean-burning candle is not enough to pose a health hazard or risk.  According to the National Candle Association (NCA), this amount of soot produced by a candle is equivalent to the smoke produced by cooking oils or a kitchen toaster. 
  • This information is listed in the “4 Common Candle Myths Debunked” post found on the NCA website at

MYTH #3:  Some candle waxes are better than others.

  • Are there some candle waxes that burn better, or cleaner, than others?  According to the National Candle Association (NCA), “an international study was conducted on soy wax, paraffin wax, beeswax, and other commonly used waxes.  Findings showed that all well-made candles exhibit the same clean burning behavior, and pose no risks to human health or indoor air quality.”
  • This information is listed in the “4 Common Candle Myths Debunked” post found on the NCA website at
  • I think this reiterates the fact that it is the fragrances and additives that are added to the candle wax that makes them burn unclean or alters the candle’s burning properties.  Also, using appropriate candle-making procedures is crucial for a well-made, clean-burning candle.

MYTH #4:  There is still lead in some wicks.

  • Are there wicks out there that contain lead?  No.  While it is true that the Environmental Protection Agency (EPA) identified lead wicks as a public health concern, the use of lead candle wicks was banned in the United States in 2003.  According to the National Candle Association (NCA), their members have not used lead wicks since the 1970’s. 
  • The NCA states, “there is no longer any reason to be concerned about lead wicks – or the toxicity of any candle wick material.”  The NCA assures us candle wicks no longer contain lead and repeated scientific studies have shown candle wicks are safe and non-toxic.  This quote is taken from the “4 Common Candle Myths Debunked” page from the NCA website at
  • Why do some candles have metal-core wicks?  Aren’t metal-core wicks the same as lead wicks?  According to the NCA, “Metal-core wicks are sometimes used in container candles and votives to keep the wick upright when the surrounding wax liquefies during burning.  Today’s metal-core wicks are made with either zinc or tin.  Scientific studies have repeatedly shown both zinc and tin-core wicks to be safe and non-toxic.”
  • There is no lead in metal-core wicks.  Metal-core wicks are made of zinc or tin.  This information was taken from the FAQ page of the NCA’s website:

MYTH #5:  Burning candles makes your walls turn black.

  • Does burning candles make your walls black?  Candles can leave residue on walls, if not burned properly.  This residue can start to build up over time if the candle continues to be burned improperly and the person does not do anything about it. 
  • Some people believe that candles ruin walls and leave black marks (soot) on the walls.  However, if you burn your candle right, it should not and WILL NOT turn your walls black!
  • If your candle is leaving a residue behind, this should be noticeable in the early stages, BEFORE the surfaces start turning black.
  • If you do have soot in your house, keep in mind that candles are not the only cause of soot.  Other sources of soot are space heaters, furnaces, fireplaces, cooking, oil lamps, and cigarette smoke.
  • The first indicator that you have a soot problem would be noticing your curtains, couch, chair, or other white or light-colored upholstery fabrics are looking a little “dingy.”  Soot can create a “gray” color to appear on these types of surfaces.

Through my research I came up with this list of tips to prevent candle soot and how to get rid of the soot residue, or black marks, if you have them.

Tips to Remove Candle Soot

Okay, now that we know “the truth,” what candle soot is, and what causes it, what can we do about that black soot you may find in your home?

Here are 5 tips to remove soot from walls.  What removes soot from walls?

  1. Dry Cleaning Sponge (aka chemical sponge) – latex rubber sponges, no water.  Start with taking a chemical sponge (or dry cleaning sponge), without any water, to clean the black soot from the wall.  These are essentially rubber sponges that do not require water to work.  Take the chemical sponge and start wiping in a downward motion to pick up the black soot.  Do not use a scrubbing or rotating motion, because this may actually cause the soot to embed further into the wall or spread the stain further.  Start in one area and work your way across the wall.  Use a new, clean sponge as necessary.
  2. Sponge and degreasing cleaner.  If this is not working or you require a heavier-duty cleaning method, use a sponge and degreasing cleaner to wipe down the wall.  Use the same type of technique, wiping in downward strokes and not rubbing, scrubbing, or using a circular motion to clean.
  3. Vinegar.  Another method you could use is vinegar.  You could mix it with water as well to dilute the mixture.
  4. Rubbing Alcohol – dab and blot.  Lastly, try rubbing alcohol, using a dab and blot method. 
  5. Soap and water.  Once the wall is clean, use regular liquid soap or a dishwashing detergent, like Dawn or Palmolive, to rinse the wall.  Mix the soap with water and use a damp cloth to rinse off any last cleaning chemicals.  Once you are done, dry with a clean towel.

Tips to Prevent Candle Soot

Finally, the best option is to prevent candle soot.  Sooting comes from a candle that is not made properly or improper burning techniques.

Here are my tips for preventing candle soot:

How to Prevent Burning Candles from Ruining or Staining Walls

Tips for the candle purchaser/user/burner:

  1. Keep wicks trimmed.  Wick should be kept to no longer than ¼ inch.  Before you light the candle, check the wick and trim, EVERY TIME!  You could trim the wick as short as 1/8 inch, if necessary.
  2. Keep an eye out for mushrooming.  If you notice your wick is starting to mushroom, extinguish the flame, and trim the wick.  Once you have gotten rid of the black ball on the end, you can re-light your candle.
  3. Keep your melt pool clean.  There should be no dirt or debris in the wax pool, which could be picked up by the flame.
  4. Keep candles away from drafts, such as open windows and air vents.  You want to keep the flame as stable as possible.  Also, avoid having people walk or run by the candle, which will disturb the air flow and cause the flame to flicker.     
  5. Avoid moving the candle, which will disturb the flame.  Once you light the candle, leave it be!  If you want to move the candle, blow out the flame and then move it.  Otherwise, position the candle where you want it first, BEFORE you light it!
  6. Do not place the candle close to walls or other flammable materials, such as drapes (that can stain).  Most soot marks on walls happen because the person has placed the candle too close to the wall.  Keep the candle at least 1-3 feet away from a wall to prevent candle sooting.
  7. Get/use a high-quality air filter.  A high-quality air filter will pick up any debris, dust, or impurities in the air.

How to Prevent Candle Soot (For the Candle-Maker)

Tips for the Candle-Maker:

  1. If you are making the candle yourself, make a quality candle!  Do your research!  Make sure you understand what you are doing!  You should know what type of wax, wick, fragrance, etc. you should be using for the type of candle you are making.
  2. Your wick makes all the difference:  Cotton wicks are more clean-burning, because they are less likely to produce soot than other types of wicks.  This is because they do not produce as much carbon.  Cotton wick absorb wax very well.
  3. Go easy on the fragrance.  Too much fragrance, or a high fragrance load, can cause a wick to clog and produce mushrooming.
  4. You want it hot!  You want the flame to be hot.  A cooler burning flame will release more soot, because the chemical reaction is not complete – there will be more carbon atoms released into the air.  Therefore, you should probably use a wax with a higher melting temperature.

Soot-Free Candle Options

Luckily, my candles have not created any soot on my walls.  I’ve only had the black marks appear on the side of my glass jar container candle.  However, I don’t think it is luck, I think it has been due to following these preventative tips/measures.

One last myth I wanted to discuss is the myth of a soot-free candle.  There is no candle out there on the market that can be guaranteed to be soot-free, due to the various reasons I already discussed.

All candle waxes could cause sooting.  However, there are some waxes that are purer than others, but just be aware that there is a risk for sooting with all candles, based on the situations/scenarios I described previously.

For example, beeswax has the reputation for being a clean-burning wax, most likely because there is very little fragrance and additives that are added to beeswax.  Beeswax has a natural honey color and scent.  It does not mix well with other fragrances or dyes.

Soy wax is another good option for less soot or soot-free.  However, keep in mind that soy wax does not bond as well with fragrances, dyes, and additives as paraffin wax does. 

Soy wax has been known to cause mushrooming, especially if the candle has a high fragrance load.  But, if you have pure soy wax with no to very little fragrances and additives, it should burn fairly clean.

If you are interested in my wax recommendations, you can check out my recommended products page here.

I hope you found this information helpful and Happy Candle-Making (or burning)!

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