You can take authority over unfriendly ghosts, as I described earlier, but I forgot to mention an important step. I want to make sure everyone stays safe, so make sure you pray for a hedge of protection before you begin commanding them to go. God *will* protect you, but you must pray for him to send a hedge of angels to protect you in battle. Don't try to have a conversation with the things, don't get angry and challenge them, just keep commanding them in the name of Jesus to go. Don't back down.
P.S., Stay away from Ouija boards. If you do it anyway and beasts come through, just remember the simple instructions above.