To get rid of a possum, identify where it lives, and place some flexible sheet metal to prevent it from climbing structures if the animal lives in a high spot, such as a roof or attic. If the possum is living under a house or deck, make sure that the animal is not in its home, and seal the entry point.
The possum is likely to leave the home on its own if it is uncomfortable, so don't leave trash cans open and don't leave any animal food lying around after dark. You can also install sprinklers or lights that have motion sensors on them and place a radio next to the possum's home to make it uncomfortable. In addition, this animal doesn't like the smell of seaweed, so place a seaweed-soaked cloth next to its home.
To find out how the possum enters its home, look for possible entry points through which it might get into the garage, house, deck or other place where you've seen or heard the animal. Coat the floor in front of the entry points with some flour, and check them shortly after dark. If there are footsteps on the flour, you have found the entry spot. To prevent a possum from entering its house that is elevated from the ground, place a 2-foot-wide band of roof flashing around tree trunks and poles that are close to the house. In addition, remove the parts of the tree branches that touch your house's roof.