Most of us don’t immediately associate rats with a powerful sense of smell in the same way we do dogs, but rats actually have very impressive snouts. As scavengers, rats always need to be able to detect nearby food sources; a strong sense of smell is an invaluable tool for sniffing out meals.
Their keen noses often bring rats into people’s properties, but we can also use those same noses against them. Just as certain scents will attract nearby rats to investigate, certain aromas also send them scurrying away.
One of the most common scents used to repel rats and mice is peppermint oil. Peppermint has the advantage of being pleasant to human noses, although rats find the powerful scent overwhelming. To use peppermint oil as a rat repellent, you should coat some cotton balls in peppermint oil and then set them down near any entry points rats are using to access your home.
You might also want to place them around your attic or loft space and in your basement or cellar if you have one. The oil will evaporate, so you will need to check them and reapply the coating as needed. Some people recommend soaking the cotton balls in the oil, but this will create a much more powerful aroma that might be too much for some people. Other essential oils that you can use in the same way include citronella oil and beaver oil. Anything with a pungent smell that isn’t food can work.
Other people have reported success using crushed peppers and onions placed in a small bowl and left near windows and cracks in the wall that rats might climb through. However, the effectiveness of these methods seems to vary quite a lot. If rats remain in your home for more than a few days, you should call a professional pest controller.