Things You'll Need
Hard bristle brush
While your toilet's tank only has clean water flowing through it, instead of human waste, hard water deposits and other buildup can accumulate on the inside of the tank, making it look unsightly. The buildup may even interfere with the operation of the toilet, such as preventing the flapper valve from sitting flat against the bottom of the toilet, leading to water leaking out of the tank continuously. When cleaning a toilet tank, avoid using harsh cleaners, since they will harm the flapper and other parts in the tank.
Turn off the water to the toilet by twisting the water valve's handle clockwise until it stops. Press the toilet's handle once to empty most of the water from the tank. Remove the tank's cover and sponge out rest of the water, wringing the sponge out into a bucket.
Pour vinegar into the toilet's tank until the stains or deposits on the sides of the tank are submerged in the vinegar. Leave the vinegar sitting in the toilet's tank overnight, and then flush the toilet the next day to empty out the vinegar.
Turn the water valve's handle counterclockwise until it stops, refilling the tank with water. Scrub any leftover stains or deposits on the inside of the toilet tank with a hard bristle brush. Repeat the cleaning process again if the inside of the toilet tank still is dirty or has deposits.