As candlemakers I think we all aim to produce a soot free candle. We also know to keep our wicks trimmed etc. when we burn them. I have burned yankme with a candle shade and the whole thing would be black with soot. If you were burning a lot of these in your house over a period of time then it only stands to reason that the soot is going to cling to walls, drapes, carpets and filters ( the same way cigarette smoke will build up if you smoke in the house ) Among other things my brother sub-contracts to an Insurance Co. as an adjuster, testifies in court when needed etc. Because of the damage caused to homes by candle soot he refuses to burn any at all in his house ( not even mine:rolleyes2 ) He said that he can tell after a walk through whether the black stuff is candle soot or a furnace problem. And he does check. Even if you dont see any soot it may still be there.