With improper exhaust in the houses and using coal or firewood for our purposes often we do not take care of the consequences because of ignorance. This settled smoke in the house invites negative energies, which may cause unimaginable situations. Use proper exhaust and where it is not possible, frequently clean the smoke and its stains or black spots. 136 ideas available in this link : https://www.subhavaastu.com/daily-vaastu-tips.html - Dhanyavaadh.