A cast iron bathtub adds charm to any bathroom, but if it is not properly cleaned and cared for, it can become discoloured and unattractive. Cast iron bathtubs are covered with a porcelain enamel that is fused to the cast iron with high heat. Cleaners that contain acid and scratchy cleaning accessories such as steel wool may leave the porcelain stained and pitted and should be avoided. Cleaning the tub regularly will reduce the amount of stains.
Combine baking soda and warm water to form a paste. Apply the paste with a sponge or rag to any areas that have soap scum or oil on them and allow it to sit for several minutes.
Rub the paste into the tub gently with the sponge. Rinse thoroughly with warm water.
Mix together 1 tablespoon of liquid dish detergent and 1 gallon of hot water.
Wipe the entire tub down with the detergent mixture using a clean sponge. Rinse thoroughly with clean water.
Choose cleaners that have a ph level between 3 and 8 to avoid using to much acid and damaging the tub.
Never use abrasive cleaners on a cast iron bathtub. Use sponges or soft rags to clean and avoid scrub brushes or other harsh cleaning utensils.