Before you strike a match, trim the wick to 1/4 of an inch every time to minimize sooting. Keeping candles away from moving air will help them burn more cleanly. To boost your candle's performance, light the candle for up to 3 hours at a time. Once the candle is extinguished, allow it to cool completely. If you do see sooting on your candle, easily remove it with a wet paper towel or wipe the inside of the glass (once cool).