Department of Health and Human Services

Cleaning Moldy Non-porous
and Semi-porous Materials

When cleaning non-porous (metals, glass, hard plastic) and semi-porous (wood, plaster, concrete) materials, follow these steps:

• Wear protective equipment and follow safety procedures (see Health Precautions During Mold Cleanup and Removal).
• First, wet the moldy area down by spraying lightly with a water-and-detergent solution to help keep mold dust and spores from getting into the air. A high-efficiency particulate air-filtered (HEPA) vacuum cleaner can also be used to help in removing surface mold growth and removing the spores from nearby materials.
• Using a non-ammonia soap or detergent and hot water or commercial cleaner, thoroughly scrub all moldy surfaces.
• Rinse the scrubbed surfaces with clean water. A wet-dry vacuum may be used to collect excessive water.
• After cleaning, a disinfectant solution such as household bleach and water (¼ to 1½ cup liquid chlorine bleach to one gallon of water), can be applied to the affected surface. Never mix bleach with ammonia - toxic gases can be created. Follow all label directions on all products used in this step. Make sure the area is well-ventilated when using disinfectant solutions. For this step to be most effective, the disinfectant solution should be allowed to stay on the surface for 6 to 8 hours and the solution should be allowed to dry naturally.
• After cleaning and disinfecting, the affected surfaces should be dried out as quickly as possible. The use of fans and dehumidifiers may speed up this process. If materials are not dried properly, the mold is very likely to re-grow. Moisture levels in wood should be less than 12 to15 percent prior to rebuilding, painting, etc.

Related Pages

• Mold Home Page
• Health Effects of Indoor Mold
• Where Does Mold Grow?
• Conditions that Promote Mold Growth
• Cleanup and Removal of Mold
• Hiring a Mold Consultant or Contractor
• After the Flood: Getting back into your home safely
• Related Websites