Things You'll Need
Small propane tank
Propane insect fogger
Large radiator hose or similar heat resistant flexible pipe
Rats spread as many as 35 different diseases to humans and are both dangerous and destructive. Eliminating an infestation is not always an easy task though. Using a spring trap to try to get rid of rats is slow -- and places your fingers at risk. The simplest way to catch rats during the day is with a rat smoker. If you are handy, you can build your own.
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Locate the mesh end of the insect fogger where the fog emerges.
Slide the large radiator hose over the end so that the mesh is entirely covered. Ensure that the hose is both long and flexible enough to allow you to direct the smoke.
Connect the propane tank to the fogger.
Fill the fogger's reservoir with 1/2 cup of vegetable oil.
Locate the rat den. Search for the probable food source, as rats prefer to live near food. Look for footprints or droppings that may lead to the den. Once you locate the den, examine the area and find all of the possible exits. Seal them, but leave at least two open.
Light the smoker. Using the attached hose, direct the smoke into one end of the rat den while observing the exit. The rats will emerge as their den fills with smoke.
Historically, rat terriers have been used to eliminate rodent infestations. Smoking the rats into the open is one way to start a lively hunt.
Be careful when lighting the propane smoker. Do not use it inside.