Mold and mildew can be unsightly and dangerous to your health. Stop mold and mildew from growing by washing down the area with vinegar. Let this dry over night and then seal with an oil based paint.
Mold and mildew can't continue to grow without air and sealing this area where mold or mildew was growing will also give your walls or ceilings a nice new look.
Soaking your material in lemon juice and setting it out in the sun to dry is going to kill off mildew smells that are in your clothes.