1/4 cup Borax in 2 cups water – Borax acts as a mold inhibitor.
(You could wash down the bathroom walls, etc. with Borax solution and just let it dry.) Heat also helps get rid of mold – it dries it to powder so it is more easily cleaned. Once cleaned, sprinkle area with Borax to prevent more mold.
To prevent mold growth, ventilate well with a small fan. or: for mildew a mixture of Lemon juice or white vinegar and salt.