Anything with a wick, that burns generates soot.....
I posted the following to another similar question last week:
These are considered safe air fresheners around birds:
• Allspice – simmered in slow cooker
• Allspice – simmered in slow cooker
• Almond Extract – simmered in slow cooker
• Cinnamon Sticks – simmered in slow cooker
• Citrus Peels - simmered in slow cooker
• Cloves – simmered in slow cooker
• Ginger – simmered in slow cooker
• Vanilla Extract & Beans simmered in slow cooker
While the following cautions and warnings are for humans and other animals, similar and/or more serious results could be expected in birds:
• Bergamot – Certain furocumarins (including bergapten found in Bergamot) are photo toxic on human skin. This causes sensitivity and skin pigmentation when exposed to sunlight.
Therefore exercise caution when using Bergamot in sunny weather. Bergamot should never be used undiluted on the skin. Severe burning may result.
• Clary Sage - Do not use in the first Three Months of Pregnancy. Can give headache (in larger doses). Do not use with Alcohol.
• Clove – All the three clove oils (bud, stem and leaf) are skin and mucous membranes irritants; bud and stem oils can also cause dermatitis. Clove bud oil is considered the safest and the only one recommended for aromatherapy use, but even so should be used sparingly, and in low dilutions (less than 1%).
• Eucalyptus – Toxic if taken internally. [Note: Many species of Asian rim parrots eat eucalyptus leaves, however, little or no information is available about Eucalyptus affects/toxicity on/to other birds, the thinking being that it is natural to a bird's natural environment and their species eats it, the specie has a built in acclimation to the eucalyptus]
• Geranium – It can lower blood sugar level, so it is best avoided by hypoglycemia sufferers.
• Juniper Berry – Not to be used in pregnancy and by those suffering from kidney diseases.
• Rosemary – Rosemary is generally regarded as safe and well tolerated, however excessive intake can cause spasm, vomiting, diarrhea, uterine bleeding, kidney irritation, and in some cases, coma. Rosemary should not be used during pregnancy or by epileptics.
• Tea Tree Oil – The International Society Of Professional Aromatherapists recently suggested that the application of tea tree oil (often found in shampoos and lotions) might cause adverse reactions in dogs. Other studies indicate possibility of similar reaction in cats and horses.
CyberCanine.com advises that:
“You should never use essential oils near your birds, on your birds nor ever diffuse oils near them.”
Bird’s Encyclopedia of Aromatherapy states:
“Do not be misled by claims that somebody’s oils are “100% pure and natural, and therefore safe as Mother Nature intended”. Momma Nature created a lot of highly unsafe things - try 100 % pure and natural snake venom, for instance.”
Gillian Willis, on Gillian’s Help Desk webpage, offers a companion human’s experience with tea-tree oil:
“The owner of a lovebird applied one drop of tea tree oil to a bleeding blood feather of her lovebird. Within 10 minutes the bird collapsed and was on the bottom of the cage. The bird was rushed to the vet. Fortunately, with intensive care treatment, the bird recovered uneventfully.”