Can candles claim to be soot free? NO, all candles have some kind of soot. The only way is when the flame is very blue like on a gas stove or a propane torch.

Soy wax is all natural and will not produce black soot like the paraffin containers have on the sides. The soot produced by soy wax is a lighter whiter soot. When you have flame and combustion you will have soot. Also when you add synthetics such as fragrance oils and dyes you will have soot. If you have too large a wick or incorrect wick it will produce soot. Also poor performing candles will cause soot. You need to keep the wicks trimmed up.