There are a number of methods that may work to keep possums away, such as building a solid fence, using motion-activated sprinklers or lights, and commercial pest repellent sprays and powders. Other effective solutions include sprinkling mothballs, hot sauce, molasses or ammonia around the property.
One of the best ways to keep possums away is to not provide them with a food source, as they continually return after finding food even just one time. They are known to cause a huge mess, scattering garbage cans and their contents, eating everything out of the garden, and stealing pet food.
If the possums ignore the repellents and continue to visit the property, the only option remaining is to trap them or hire a pest removal company for the job. Most possums are trapped using box traps, which are readily available at hardware stores or the local animal control office. These traps don't harm the possum, but simply lock him up so that he can be relocated.
The laws concerning the relocation of animals differ from place to place, so one should always make sure to check before trapping. If relocation is legal, it is important to move the opossum at least five to 10 miles away. Leg snare traps can also be used to trap a possum without hurting him, but some people also use kill traps that suffocate the animal.