Not all scented candles have odour-eliminating capabilities. Some candles use traditional fragrances that mask unwanted odours by overpowering them. Sometimes that works, and other times, the scents merge to create an equally unpleasant or worse odour. Then some candles have proper odour-eliminating technology. When burnt, they release odour-neutralising enzymes that attack and break down the pungent smell on a molecular level, reducing or removing the scent and replacing it with a much more appealing aroma. If you have a specific odour you need to remove, find a candle designed to eliminate it.