Our candles produce a clean flame which does not release any toxins into the air. Soy wax lasts longer than other candle waxes due to a lower burning temp. Our glass candles will burn for appox 25/35 hrs. They should only be lit for 2/4 hrs at a time and by allowing the wax pool to melt to the sides it will prevent tunnelling and let the fragrance gently defuse into your home.