Distilled Vinegar

• Distilled vinegar contains 5 percent acetic acid, which can kill mildew with little effort. Pour the full-strength vinegar into a spray bottle and attack mildew wherever it occurs. Rinse 15 minutes after applying. Other acids, like citric acid, also can kill mildew, so also try using lemon juice to kill mildew. Avoid using acid, including vinegar, on granite or marble.
  
  

Bleach

• When applying bleach to a mildewed surface, you have three options: chlorine bleach, hydrogen peroxide and oxygen bleach. Chlorine bleach is the most invasive of the three, and contains potentially dangerous chemicals. As a result, add 1 quart of water to each cup of chlorine bleach before applying. Hydrogen peroxide and oxygen bleach are both natural, oxygen-based bleaching agents, but hydrogen peroxide typically comes in liquid form while oxygen bleach typically comes in powder form. Also, oxygen bleach works more effectively than peroxide bleach due to a more reliable release of oxygen ions.
  
  

Borax

• Borax is a powerful chemical compound that you can safely apply to the most porous surfaces, making it ideal for use on upholstery and fabrics. You can find commercially packaged borax at hardware stores and home improvement stores. Before applying, mix 1 part borax with 4 parts hot water. Do not pour the borax solution over your surfaces, but instead use a cloth or sponge to gently dab the mildew.
  
  

Clear Ammonia

• Clear ammonia is a pungent but powerful mildew killing solution. Due to its heavy chemical concentration, add no more than 1 cup of ammonia to 1 quart of water for application. If cleaning wood or painted surfaces, Reader's Digest recommends adding 1/2 cup of vinegar and 1/4 cup of baking soda to the solution. Do not ever mix bleach with ammonia, nor apply ammonia to an area that you recently cleaned with bleach.