If a wild animal has gained entrance to a crawl space or attic, close all but one point of entry. To determine which hole is being used as a point of entry or exit, cover all holes with a piece of plastic or stuff a rag or ball of paper into it. If it is gone the next day, the hole is being used. You can also try shinning a bright light into their home. What you can do to prevent problems from occurring The two most effective and humane solutions are to secure your garbage so that you do not attract and feed wildlife and to secure your home so they cannot find convenient shelter.
Garbage cans are to raccoons and opossums what bird feeders are to cardinals and doves.
If you cannot pull the cover away bare-handed, you will have defeated any effort made by animals to gain entry. Your garbage can should have a lid that fits tightly. If this isn't possible, you might try hooking a bungie cord from one side of the can to the other to secure the lid. Or you could try placing a large rock on top of the lid to secure it. Usually raccoons gain entry into garbage cans by tipping them over.