Pour 1/2 cup of white vinegar into a bowl. Add 1 teaspoon of table salt to the vinegar and stir with a spoon until the salt has dissolved.
Sprinkle white flour into the salt and vinegar solution while stirring constantly. Add enough flour to make a paste.
Dip an old toothbrush in the vinegar-based paste. Apply it to the calcium deposit stains on your bronze hardware until the stains are covered.
Wet paper towels with undiluted white vinegar. Lay the vinegar-soaked towels over the paste-covered bronze. Leave the paste and paper towels in place for 10 to 20 minutes to dissolve and loosen the calcium deposits.
Remove and discard the paper towels. Wet the toothbrush with water. Scrub the bronze hardware to remove the loosened calcium deposits.
Wipe the bronze with a damp cloth to remove the stains and paste mixture. Dry the bronze surface with a dry cloth.