Ouija Board is not a game. For those who dont know what comes with it, should not touch it.
Somebody who knows how to do it should be the medium as every session should be ended properly, that is if you believe in spirits, elementals and the unworldly.
What you called for during the session should be released / returned where they came from. If not, they would stay in the body or energy field of the one who subconsciously allowed himself to be the "host". Beware! Ignorance excuses no one.