Tile grout is used as a waterproof sealant to fill the cracks between individual tiles. This mixture of cement and sand (and colouring compounds for coloured grout) forms a very effective barrier against water seepage. Over time the waterproofing capability of the grout diminishes with constant exposure to moisture. Mold and mildew form along the grout in your shower stall due to these excessive moisture levels. You have the option to remove mildew from shower tile grout with both natural cleaners and traditional household bleach.
Rinse the grout areas with hot water. Use your scrub brush (without cleanser) to loosen the mildew in the grout. Rinse any mildew from the grout.
Pour one-half cup of baking soda into the bucket and mix it thoroughly with a gallon of water. Baking soda is an all-natural cleaning agent frequently used to boost the cleaning power of laundry detergents and can be used all around the home as a natural deodoriser. However, it also works well as an all-purpose cleaner around the house. Baking soda won't harm your plumbing or tile but it will dry our your hands, so make sure to wear gloves when scrubbing
Sprinkle baking soda along the affected areas of mildewed grout. Dip your scrub brush into the baking soda/water mixture. Adding water to dry baking soda creates a paste that is lightly abrasive yet gentle enough not to harm the shower tile. Scrub the tile grout completely, working the paste into the grout.
Let the baking soda sit on the tile grout for at least an hour to allow the cleaner to penetrate the mildew to loosen it. After an hour, rinse a small area to gauge your progress. Mildew can be quite hard to remove, so reapply the baking soda solution if necessary, scrub thoroughly and rinse again. It will not harm your grout to leave this solution on overnight.
Soak paper towels with white vinegar and place these wet cloths directly on the most stubborn mildew stains. Let the vinegar sit for 15 minutes and scrub the mildew spots. If the spots still prove stubborn, pour vinegar directly onto the mildew stains and scrub. Rinse and repeat until the mildew is removed.
Bleach the mildew spots by mixing a solution of one part bleach to 5 parts of clean cool water in a spray bottle. Make sure to ventilate the bathroom well before spraying bleach. Soak the mildewed areas completely and allow the solution to work for 15 minutes. Scrub vigorously and rinse with cool water. Repeat if necessary.