Cleaning Minerals & Deposits from Bathrooms: Cleaning Problem Areas in Bathtubs to deposits

I find this procedure from god’s word, the bible, works best for killing mildew:
To purify the house of mildew take two birds, cedar wood, scarlet yarn and hyssop. Kill one of the birds over fresh water in a clay pot. Then take the cedar wood, hyssop, scarlet yarn and the live bird, dip them into the blood of the dead bird and fresh water, and sprinkle the house 7 times. Then he is to release the live bird in the open fields outside the town. In this way it will be clean.” [Leviticus. 14:48-53]