Vinegar contains a mild acetic acid that makes it a reasonably effective general-purpose cleaner around the house. While vinegar is nontoxic to humans, it reportedly kills many types of household mold. However, killing mold isn't really the point: mold spores are everywhere in the air we breathe, and anywhere the conditions are right for mold growth the problem will come right back. Therefore, the true objective of killing mold is to remove it from the surface then eliminate the conditions that lead to mold growth.
If you're cleaning a hard surface, such as a sink or tile wall, all you really need to do is remove the mold with soap and water, which are the ingredients recommended for mold removal by both the EPA and Health Canada. Drywall, fabric and other porous materials that are affected with mold and moisture damage must be discarded.
Disinfect If Desired
Vinegar has some effectiveness as a disinfectant, so you might want to follow your initial cleaning with a vinegar treatment to help eliminate bacteria. Use a 5 percent solution -- the concentration of straight, undiluted vinegar on the grocery store shelf. Pour full-strength vinegar into a spray bottle, or soak a sponge or cloth with it, and saturate the area. Give the vinegar some time to work -- anywhere from 15 minutes to an hour -- and wash it off. For maximum disinfecting, you can skip the rinse and just let the vinegar dry. Don't worry -- the smell will dissipate a few hours after cleaning.
Mold needs moisture to survive. If you eliminate moisture, you prevent mold growth. Mold is common in bathrooms simply because it's a wet environment. Eliminate moisture there by drying out the air with a good ventilation fan, running it during and after each bath or shower. Regular cleaning should keep mold at bay in the shower itself.
Elsewhere in the home, seal cracks that let in water, and use natural ventilation or a dehumidifier to lower humidity in moist areas like basements and crawl spaces. Fix water leaks as soon as possible, and dry the area thoroughly to prevent mold growth. If mold has already taken hold in an area around a leak, remove any soft or porous materials that are moldy, then clean the mold from wood and hard surfaces.
Vinegar in the Bathroom
Vinegar is an ideal cleaner for moist walls in bathrooms, shower stalls and tub alcoves because it dissolves hard water deposits while it kills mold. If you simply spray it on walls, though, it will run off before it has a chance to do its work. To prevent this, make a paste using borax as a thickening agent. Spread the paste liberally on the walls with a cloth, and leave it for an hour or two, spraying occasionally with full-strength vinegar to keep the paste moist. When you rinse the paste off with water, the white film from lime deposits and soap scum will go down the drain along with the mold. Note: The acid in vinegar can etch some types of stone and stone tile; consult your stone supplier or installer for recommendations.