It should be burning cleanly for you without soot or smoke and it should not be tunneling, i.e. the should be no wax residue left on side of the glass. When a soy candle is nearly burnt down, you will notice that the good ones still do not smoke or soot but the lesser ones will and you may notice some soot appearing along the top of the glass. A further sign of a high quality perfumed soy candle is that the wick does not develop a glowing ‘mushroom’ head. In the past, you may have noticed that some candles develop red glowing bubble or head that eventually drops off into the wax to create an unsightly mess in the wax. This happens usually because something in the engineering of the candle is not quite right (the wick, the fragrance, some additives, etc.). However, here at PAIRFUM we do not accept this in our candles. Every PAIRFUM candle will burn down cleanly and completely, will not soot or smoke nor will it leave soot marks on the glass or tin. The best soy candles are made from 100% natural soy wax without any synthetic or petroleum derived additives. These additives are not necessary and yet many candle companies blend soy wax into a paraffin wax candle. This i...