When a mouse dies in a vent, it stinks. When the heater runs, it forces that bad smell into the house. Not only does the mouse cause a foul odor, but it can also attract gnats and flies. The smell is often the first sign people receive alerting them of the dead rodent. The smell sticks to the surfaces of the vent the mouse touches. Bleach cuts through the smell and kills the germs left behind by the mouse.
Turn off the heat and air conditioner (if applicable).
Put on a pair of gloves. Take off anything covering the vent. Remove the dead mouse. Throw it in a plastic bag. Tie the bag closed and throw it in an outdoor trashcan.
Pour bleach into a bucket. Add 1/2-gallon of water.
Put on a pair of rubber gloves. Dip a sponge into the bleach water. Mix up the bleach and water with the sponge for 10 seconds. Lift the sponge over the water and squeeze it to remove the extra liquid.
With the sponge, wipe out the vent where the mouse touched.
Wet a clean sponge with water. Wipe off the bleach water with the sponge.
Let the vent dry completely before turning on the heat or air conditioning.