Get Answers to Disaster Clean-up Questions from Extension’s Answer Line

Answer Line callAMES, Iowa – After tornadoes, floods and other disasters, Iowans wonder what, if anything, they can salvage when they return to their homes. So they’re asking the professional family and consumer scientists at Iowa State University Extension’s Answer Line, 800-262-3804.

Here are a few of Iowans’ disaster-related questions and Answer Line’s answers.

No electricity ...

The electricity was out for six hours. Must I throw away everything that was in my refrigerator?
Many foods do need to be thrown away if they have been above 40 degrees F for more than two hours. However, a few foods can be saved if they have no sign of spoilage. That would include hard cheese such as Cheddar, Swiss, Colby, Parmesan, Provolone and Romano as well as processed cheeses. Other foods that may be edible include margarine, butter, whole fresh fruits, dried fruits, jelly, relish, pickles and vinegar-based dressings.

May I refreeze the food in the freezer if it thawed or partially thawed?
Yes, the food may be safely refrozen if the food still contains ice crystals or is at 40 F or below. You will have to evaluate each item separately. Be sure to discard any items in either the freezer or the refrigerator that have come into contact with raw meat juices. Partial thawing and refreezing may reduce the quality of some food, but the food will remain safe to eat.

No drinking water ...

We have been told not to drink the water that comes from the tap.  What should I do to disinfect the water so we can use it?  
If you don’t have bottled water, you should boil water to make sure it is safe. Boiling water will kill most types of disease-causing organisms that may be present. If the water is cloudy, first filter it through clean cloths or allow it to settle, and then draw off the clear water for boiling. In any case, boil the water for one minute, let it cool, and store it in clean containers with covers. In addition to using the disinfected water for drinking, it also should be used for ice, cooking, washing cuts, brushing teeth and rinsing clean dishes.

Dealing with mold ...

Can I test my house for mold?
In general, testing for mold is not recommended. Instead the money and effort are better used getting rid of the mold and the moisture that causes it. Also, the color of the mold does not matter. All mold can have negative health effects, so it should be removed. This also is true whether the mold spores are living or dead. The mold needs to be physically removed.

For specifics on how to remove mold from a flood-damaged home, download a free copy of Storm Recovery Guide (SP 327) from ISU Extension’s Online Store, This document was created by Louisiana State University AgCenter and has been adapted for use in Iowa by ISU Extension.

How do I prevent mold in my home?
Molds usually are not a problem indoors, unless mold spores land on a wet or damp spot and begin growing. Molds produce tiny cells called spores that float through the air. When the spores find the right conditions – moisture, nutrients and a suitable place to grow (conditions that abound after a flood) – they begin forming new mold growth. Moisture is the key factor; you have to control moisture to control mold growth. Remove any mold that is found and keep the surface dry to prevent future growth of any mold. Do not expect any special product to stop mold growth. 

Damaged wood furniture ...

How do I remove white spots that have developed on wood furniture that was damp but not submerged in water? 
A cloudy film or white spots on furniture that has been damp can probably be removed. Protect yourself by wearing rubber gloves. Rub with a damp cloth dipped in either turpentine or camphorated oil. Another choice is to dip the damp cloth in a solution of ½ cup household ammonia and ½ cup water and rub. Wipe dry immediately and polish with wax or furniture polish. On deep spots, use a drop or two of ammonia on a damp cloth. Rub with a dry cloth and polish. Rubbing cigarette ashes, powdered pumice or a piece of walnut into spots also may help remove them. If spots remain following these treatments, the piece should be refinished.

That stuff on the basement wall ...

What is the crystal shaped deposit on my basement wall? I know it is not mold.
It most likely is efflorescence, a crystalline or powdery deposit on the surface of masonry materials like concrete, brick or clay tile. Appearing fluffy or fuzzy, it is usually white but may be other colors. It develops when water seeps through the wall or floor. The water dissolves salts inside the object while moving through it, then the water evaporates, leaving the salt on the surface. Efflorescence can be removed because it is salt. Most salts are water soluble and can be removed by high-pressure water jet, light sandblasting or dry brushing. The heavy accumulations or stubborn deposits may require washing the stains with a dilute solution of muriatic acid (1 part acid to 12 parts water) and scrubbing with a stiff bristle brush. Dampen the surface with clean water before applying the solution. After scrubbing thoroughly, flush with clean water to remove all traces of the acid. Then paint with a masonry water proofing paint, not a water sealer. Excavating around the home and waterproofing with tar or membrane is probably the best remedy to efflorescence. 

ISU Extension’s professional family and consumer scientists answer questions about child development, cleaning, consumer management, food preparation, food preservation, food safety, home environment, household equipment, nutrition, textiles and laundry. For answers to your home and family questions, call Answer Line, 800-262-3804, Monday through Friday from 9 a.m. to noon and 1 to 4 p.m. Or visit the Answer Line website,, or e-mail

For additional disaster recovery information, see ISU Extension’s Recovering from Disasters website,


Answer Line from Iowa State University Extension.