Mold and mildew fungus thrives in the moist environment of a toilet tank. With regular cleaning, mold growth is easily prevented or removed. But when the toilet tank has been forgotten for awhile, you might be appalled to discover mold spores inside once you finally remove the lid. Although bleach and stronger cleaning products successfully kill and remove mold stains, they also introduce harsh chemicals into the water and the environment. Vinegar is a natural mold killer that cleans and freshens the toilet tank. You can get and keep a clean toilet with regular use of white vinegar.
Turn off the water to the toilet at the shutoff valve. Flush the toilet to empty the tank.
Pour 1 gallon of white vinegar into the toilet tank. Fill a bucket with water. Pour the water into the toilet tank to raise the water level above the highest mold stains.
Allow the diluted vinegar to remain in the toilet tank overnight to kill the mildew spores and loosen the stains from the sides of the tank.
Sprinkle baking soda onto a long-handled scrub brush. Scrub the inside of the toilet tank to remove the mold stains.
Turn the water supply back on. Flush the toilet to rinse out the inside of the toilet tank.
Pour white vinegar over the brush bristles and add baking soda to tackle any remaining mold stains in the toilet tank. Flush the toilet to rinse them away. Leave the lid off the toilet tank so the portion above water level can air-dry.