Mildew is a fungus that grows in damp places and therefore, is why many homeowners struggle with keeping mildew under control in their bathroom. Even if you clean your bathroom weekly and spray a shower mist after every use, you may still see the black stuff start to grow. Sometimes, it is on the seal of your shower door which is often a forgotten place or not easily seen. Since the door is usually closed, moisture often stays there for long periods of time, which is a haven for mildew growth.
Be cautious. Since mildew is not good for your respiratory system, wear a mask, safety glasses and rubber gloves when removing mildew. This will also help from inhaling or getting any contact with any strong chemicals that you may use in the cleaning process.
Use a commercial product for removing mildew or a baking soda and water paste. Let the spray or baking soda soak in for about an hour. Then, scrub the seal with a toothbrush until it is clean.
Use bleach. If the previous step does not rid your seal of all mildew, carefully use bleach. Apply the bleach with cotton swabs or sponge all over your seal. Let is soak for a few hours and the scrub with a toothbrush. For really stubborn mould, let it the bleach soak for a few hours and then reapply. Let it soak overnight and scrub with a toothbrush in the morning.
Take your shower door off and take it outside in the sunlight. Sunlight will help kill the mildew and turn it into a powder. Brush it off with a dry toothbrush onto some disposable newspaper and then scrub with a toothbrush using a commercial spray or baking soda paste.
Take off your seal and replace it. If all else fails, take off your shower door seal and scrub the area with a commercial product of baking soda paste. Replace the seal.