Humid air and poor ventilation contribute to mildew growth on bathroom ceilings. Mildew is a fungus that contains a musty odor and appears as multicolored spots on ceilings. Other than aesthetic purposes, mildew removal is necessary to prevent the spores from spreading and further contaminating the bathroom. Since mildew feeds on organic debris, such as dirt and dust, it's essential to promptly and thoroughly clean the affected ceiling before disinfecting it.
Put on rubber gloves to protect your hands. Open the windows to allow air flow into the bathroom.
Prepare of solution of 1/4 cup trisodium phosphate and 1 gallon warm water, in a plastic bucket. Mix the solution well.
Scrub the affected portion of the ceiling with the trisodium phosphate solution using a nylon brush. Wash all mildew spores off the ceiling.
Dampen a clean rag with warm water. Wipe the ceiling with the damp rag to rinse away the trisodium phosphate solution.
Mix a disinfecting solution of 1 cup chlorine bleach and 1 gallon cool water in a second bucket.
Moisten a second clean rag in the bleach solution. Wipe the moistened rag over the ceiling to kill any remaining mildew spores and disinfect the ceiling. Keep the bleach solution on the ceiling for an hour.
Dampen a third clean rag with warm water. Wipe the rag over the ceiling to rinse away the bleach solution.
Blot the ceiling with a clean towel until all moisture is removed.