Citronella oil comes from a combination of naturally bug-repellent grasses. In candle form, it masks the scents of carbon dioxide and human lactic acid, which are so attractive to insects. And it's perfectly safe too! Approved by the FDA, citronella has been used to flavor foods and beverages for more than 50 years. So, get the tutorial for citronella candles, and light them up at your next backyard party for a bug-free gathering.