Q.  Help! We put out some mouse bait in various places in our house almost two weeks ago. Apparently it worked because now the house stinks horribly from dead mice. Can you tell me what kind of product I can buy to get rid of the smell? Household spray deodorizers just make it worse. And how long do dead mice smell?

A. Dead animals will smell until they are completely decomposed or until they are dried out, whichever comes first. It goes without saying that the larger the animal, the more biomass there is to rot, the stronger the smell will be, and the longer the smell will last. Temperature is a factor; decay speeds up as temperatures increase. Also, the damper the site, the longer the odor will last. If a rat dies near a steam pipe, the body won’t dry and the smell can be horrible for weeks. The odor from a dead mouse may last only a day or two. In fact, there may be no noticeable odor from a single dead mouse but several dead mice in the same area could smell for a few days. A dead rat may smell really bad for a week, but there can be some lingering odor for as long as a month.

The obvious solution for an odor problem from dead animals is to find and the remove the animals, then ventilate the site. When you can’t find or remove the carcass, you may just have to wait it out — with some chemical help. There are several ways to deal with the odor: (1) You can take the odor out of the air by using an air cleaner with an absorbent filter. (2) You can add something to the air that neutralizes the odor. Or, (3) you can add a new, more desirable odor that temporarily masks or covers up the bad odor.

Air cleaners are devices that usually use a replaceable absorbent filter such as activated charcoal or silica gel. When room air circulates through the filter, it absorbs and removes particles. Odor neutralizers often contain bacteria or enzymes that break down the organic compounds that are causing the odor. Others use ionic minerals to neutralize odors. Some odor neutralizers also contain an artificial fragrance, but many do not. Odor neutralizers are available as powders, granules, sprays, or as rods.

Masking deodorants are highly concentrated fragrances that simply cover up the bad smell. They don’t neutralize. They can be applied as granules, aerosols, mist sprays, or released through a cotton wick. Since they have a very strong fragrance, use them carefully to be sure they aren’t more offensive than the original odor!

Accumulations of dead insects can also cause odor problems. Cluster flies and some other insects that enter our homes to spend the winter can end up in large numbers in the attic or in wall voids. If the area is treated with insecticides and large numbers of insects are killed, there can be a noticeable odor as they decay.

Odor from dead mice is one disadvantage to using rodenticide bait. The mice often die in the attic or in wall voids or other places where you can’t retrieve the carcass. Whenever odor might be a problem, you should use snap traps or sticky board traps for mice so that you can dispose of the dead mice.

Finally, you need to figure out how and why mice or other animals are getting into your home in the first place. Contact Colonial Pest for a free quote, or call us at 1-800-525-8084 right now. We can do a thorough inspection for rodents and other nuisance animals and can come up with a pest management program that will keep them out.