An effective way to remove the smell of dead rats from the house is the use of a drying enzymatic cleaner. After removing the carcass, one applies the cleaner directly to the spot, on the maggots and juices from the dead rat.
A drying enzymatic cleaner removes excessive moist from the area, reducing the time it takes to get rid of the smell. The more moist the area, the longer the odor lingers and the stronger the smell.
Bleach is another cleaner that has been effective in removing the bad smell. One should use it in a much stronger dilution than is recommended. It kills just about any microorganism, but it only covers up an odor. One should use it carefully because it could harm construction materials.
Alternatively, mix baking soda and water into a paste and apply it to the spot where the carcass was. Leaving the paste in contact for long periods and allowing it to dry, makes this method effective. However, this method is not effective if the construction material has absorbed any bodily fluids.
If one cannot locate the dead animal, using an ozone generator lessens the smell. Car cleaners use it to make vehicles smell new, and it works to break down odor molecules. Finding and removing the carcass and applying a cleaning agent is more effective that this method.