Candle oil is more commonly called kerosene or paraffin oil. The oil has been used to light lamps and candles since the 1800s and is still used in the modern world for those purposes, as well as to power space heaters and portable stoves. Candle oil is toxic when ingested, but harmless when burnt. Because candle oil is so flammable, it is best to not store it in hot areas of the home or to smoke near it. This liquid is easy to dispose of whether unused or contaminated.
Burn up any extra candle oil by leaving your lanterns on or getting replacement wicks. Keep windows open, and adequately ventilate the area where the oil-fed candle is burning, to dissipate the combustion byproducts.
Call your local mechanic and ask whether it have a space heater than runs on kerosene. Deliver dirty kerosene to the mechanic, who might have a filter that can clean the kerosene enough for use.
Take contaminated kerosene to your city or county government's hazardous-waste collection facility. Call the clerk's office and ask where the hazmat facility is. Get its phone number to find out when it's open.
Keep candle oil in a sealed contained when transporting it to a disposal facility. The oil could spill on you or something else, staining clothes or igniting near a flame.