But never be scared, that blue or black stuff in your bathrooms and kitchens is most likely mold and dirt, all properties have mold and usually start building up in wet places like bathrooms, kitchens, etc, it is nature's way of recycling. Drying is the cheapest UN-SCARY way to preserve in a healthy way. How you clean it? the same way you clean wet places, bathrooms, kitchens, and decay by yourself or by hiring help.
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