The traditional candle could become the latest weapon against harmful bacteria. Researchers from the University of Southampton have found that adding essential oils, like eucalyptus, orange and thyme to candles can destroy bugs. Dr Lindsey Gaunt and Sabrina Higgins said adding these oils to plug-in devices had a similar effect. The researchers told a conference in Tokyo that adding oils to candles could be as effective as scrubbing with disinfectants.