How to Clean an Old Porous Iron Bathtub

General Cleaning

• 1

  Select a nonabrasive cleanser. If using a commercial cleanser, choose one that specifically states on the label that the product does not scratch. You can also use a dilute solution of dishwashing detergent and water or make a paste with baking soda and water.

• 2

  Use the nonabrasive cleanser for routine cleaning of the bathtub. If you use a liquid cleanser, just apply it onto the surface of the bathtub. If you use a powder cleanser or baking soda, wet the bathtub first and then sprinkle the powder cleanser across the surface of the bathtub so you can make a paste.

• 3

  Rub the cleanser onto the surface of the bathtub using a damp cotton terry cloth, sponge or paper towels. You can use either a circular motion or a back-and-forth motion. If you are using a powder cleanser, add more water as needed to maintain a pasty consistency.

• 4

  Continue rubbing the cleanser onto the surface, moving from one area to the next until you have cleaned the entire bathtub.

• 5

  Use trisodium phosphate (TSP) to clean heavy deposits of dirt or soap scum. Mix 1 tablespoon of TSP in 1 gallon of hot water. Pour some of the solution into the bathtub and use a wet cloth to rub it onto the surface, moving from one section to the next.

• 6

  After you finish cleaning the tub, rinse it with plenty of clean, warm water. Dry the porcelain surface of the bathtub using clean terry cloth or a cotton towel.

Cleaning Rust

• 7

  Apply lemon juice to remove light rust stains. Pour the lemon juice on the stain or soak the cloth you are using in lemon juice and apply it to the stain, rubbing until it is gone.

• 8

  Use oxalic acid to remove stubborn rust stains, according to Utah State University Cooperative Extension. Add 1 teaspoon of oxalic acid to a cup of hot water. Wear rubber gloves and goggles. Apply the solution to the affected area and rub it in with a damp terry cloth. Rinse the oxalic acid solution off immediately with an ammonia solution.

• 9

  Rinse the bathtub with warm water and dry it with a cotton terry cloth or cotton towel.