Keep away from defiling things

Leviticus 14:33-57
Cleansing from defiling molds, mildew.
Anyone who goes into the house while it is closed up will be unclean till evening. Anyone who sleeps or eats in the house must wash their clothes.
To purify the house he is to take two birds and some cedar wood, scarlet yarn and hyssop.
These are the regulations for defiling skin diseases and defiling molds.
Hyssop: A herb, possibly marjoram, containing a mild antiseptic(防腐劑).
Why?
The regulation to the disease, house and clothing are setting healthy living environment.
Cleansing house need effort to make it, but it is necessary for our living. Same as we excluding sins from our life need effort to make it.
How?
Keep away from the sin and anything may lead us from God.