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Michigan State University Extension
Home Maintenance And Repair - 01500334
06/24/03

Removing Mildew From Carpets



If the musty mildew odor is detected, stop its growth. Use a dehumidifier to remove the moisture from the air and, in turn, from the carpet. As long as the moisture is low the mildew will not grow. Open up the windows and use fans to circulate air over the carpet. If the mildew growth is on the surface, open draperies to allow the sun to shine on the carpet. Even artificial light will help.

If flooding occurs and the back of the carpet is not made from all man-made fibers, dry the back of the carpet as quickly as possible. This may require the services of a professional carpet cleaner to take the carpet up and dry it at their plant. On smaller carpet or if only a portion of a large one is wet, one corner of the carpet may be lifted so fans can circulate air underneath. By attaching the hose to the exhaust of a vacuum cleaner, it can be inserted under the carpet and used to blow air.

Caution: Care should be taken when using electrical appliances around a wet carpet to prevent electrical shocks. If the carpet is dried quickly, this should prevent mildew growth.

If mildew growth has started, it will be mainly in the back. If the back can be examined, a discolored area may indicate the growth location. The musty odor will be evident if some moisture is still present. If no odor can be detected, a little hot moisture from a steam iron on the back of the carpet will quickly bring out the musty smell.

To kill the mildew once the area is determined, a rug or smaller wall-to-wall carpet can be taken outside so the back can be exposed to the direct rays of the sun, which will usually kill the mildew in a day or so. Giving the affected back area a light painting of a 1/2% solution of hydrogen peroxide (one part of fresh 3% hydrogen peroxide to 5 parts of water) and then letting the sun shine on it, will make the action take place at a  faster rate. Cleaning with a diluted carpet cleaning solution will wash the mildew from the surface but this action alone will not kill the mildew.

These procedures usually will not remove the discoloration from inside the fibers. To do this may require very destructive bleaching which can destroy the fibers.

If the carpet is returned and used under the same conditions in which the mildew originally grew, it can  grow again. Not that the mildew wasn't killed but,  rather, new mildews spores can get on the fibers.

References

This article was written by Anne Field, Extension Specialist, Emeritus, with reference from the Georgia Extension bulletin, How to Care for Carpets and Rugs, the Hoover Company, Nebraska Extension bulletin Carpet Care -  Cleaning and Stain Removal, the Carpet and Rug Institute, Allied Fibers and Plastics Inc. and DuPont Clean Up  Carpeting bulletin.

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