Bathing suits are prime targets for mildew. If you take off a wet bathing suit and toss it down in an area that is warm and not well-ventilated, you probably will be left with a musky odor on your suit. Mildew is the result of the fungal growth of mold. The smell can linger even if you launder your bathing suit. If you want to get rid of the mildew odor on your suit, treat it with a common household product.
Bring the bathing suit outdoors and brush off any visible mildew with a toothbrush. The mildew may have a white or black appearance. Brushing the excess away outdoors reduces the chance that you may inhaling mold spores while cleaning the stain. Wear a mask, if needed.
Soak the bathing suit in a container filled with undiluted white vinegar. Make sure you use enough vinegar to cover the swimsuit entirely. Leave it soaking for one hour.
Launder your bathing suit as you normally would. If you wash it in the washer, add 1 cup of white vinegar, along with your normal laundry detergent, to the washer.
Hang up your bathing suit in a well-ventilated area to dry or tumble dry it on low if the fabric's directions indicate that it is safe to do so.