Installing proper fencing, eliminating shelter, eliminating food sources and closing off entrances are ways of getting rid of opossums and make a back yard uninviting to the animal. Repellents such as mothballs, ammonia and spikes can also be used to make a back yard inhospitable to the animal. Trapping unwanted opossums is yet another way to get rid of the animal.
A 3- to 4-foot fence can be used to prevent opossums from entering a yard. The fence should face outward to prevent the animal from climbing it. Electrical fences are also an effective way to keep the animals out of yards.
Eliminating shelters, such as brush and wood piles, and clearing unnecessary debris like deep leaf litter, fallen trees, unused equipment or unused cars make a space unattractive to the animals. Food sources, such as pet food or compost piles, should be sealed, covered or moved.
Mothballs and ammonia, strategically placed, create a scent that deters opossums. The ammonia can be placed in a coffee can with a rag placed on top to disperse the scent. Urine from the opossum's natural predators, such as foxes, bobcats and coyotes, are also effective scent repellents.
Live capture traps, leg hold traps and kill traps can also be implemented to catch or kill the unwanted opossums.