Toilet tanks and bowls are made of vitreous china and are impervious to ordinary household acids. If something more than hot water and soap is needed to clean them, apply a non-abrasive powder or cleaner recommended by the manufacturer or your plumber. Many good bowl cleaners are on the market today. Most plumbers, however, have found that the chemicals in "blue water" continuous bowl cleaners tend to accelerate the deterioration of the rubber and neoprene parts in the tank.
Seat bumpers (found under the toilet seat) should be replaced if worn. Defective bumpers may cause breakage of the seat or hinges. Stains or moisture at the base of the toilet bowl indicate that the joint or seal between the toilet and its outlet have failed and should be reset immediately to prevent rotting of the floor, damage to the plaster of the ceiling below, and possible leakage of sewer gas into the home.