1. Empty the tank by locating the water valve, usually on the wall behind or near the toilet’s base. Shut it off, lift the lid from the tank and flush until it drains completely.
  2. If there’s just grime and dirt, start cleaning. If there’s discoloration from residue, fill the tank with cleaning vinegar to the overflow valve (about three gallons in a standard toilet) and let it sit for 12 hours. Then flush. You can also use dish soap to help clean. “But do not use more than a couple of drops of dish soap on the sponge or it will create a flood of bubbles,” says Geambasu. “Just a couple of drops will do and scrub the scum and mildew away and you will be fine.”
  3. Put on rubber gloves and spray the inside of the tank with disinfectant. Let the disinfectant set for 15 minutes.
  4. It might be tempting to clean it with bleach, but don’t do that because it’s corrosive.
  5. Scrub the inside of the tank thoroughly with your scrub brush.
  6. If your toilet’s internal parts need maintenance or replacement, now is the time to do it. Here is how to stop a running toilet and fix flush problems.
  7. Wipe off the internal parts to remove any slime or dirt.
  8. Turn the water back on and allow the tank to fill. Go ahead and flush it a couple of times. If it’s working, you’re done!