The bathroom may be the easiest place in your home for mold to grow. Mold grows in moist and humid areas, and repeated use of hot water in the shower creates a prime breeding place for mold. Killing the mold on a bathroom ceiling and taking steps to prevent it from coming back will keep your bathroom safe, healthy and cleanly in the future.
Combine materials for your cleaning solution in your spray bottle. A number of household items will effectively kill mold. Combine even parts vinegar and water or one part bleach to four parts water (or 1 cup of bleach for each gallon of water), for effective cleaning solutions. Pour your chosen solution into the spray bottle, and shake to mix.
Remove any items from the bathroom that can be harmed by bleach or vinegar, such as toothbrushes or bath mats. Lay your drop cloth or old piece of clothing, such as an old towel or shirt, over anything in the bathroom that cannot be removed and that you do not want exposed to the cleaner. When cleaning the ceiling, the solution may drip onto surfaces below, so protect your items as best you can.
Spray the affected area of your ceiling with your cleaning solution. Allow at least an hour for the solution to effectively kill the mold. Wipe away the remaining residue and mold with a scrub brush or rag and some hot water; add soap or detergent if you choose.
Take steps to prevent mold from returning, thus ridding your ceiling of it completely. Mold grows in humid and damp places. Dry the walls and ceiling of your shower after you are finished with it to prevent the moisture from allowing mold to grow.
Increase the ventilation in your bathroom to help prevent the mold from coming back. Turn on the bathroom's exhaust fan while you are in the shower. Open the bathroom door and windows after showering to allow the humidity and moisture to escape. Talk to a home professional about installing an exhaust fan or extra windows to increase ventilation.