how demons 'work'

Uh, to clarify, i.e. salt banishes spirits, names & histories of monsters, latin prayers etc, basically a whole lot of info normal people wouldn't know. He'd be almost as likely to have just lost the fact that other people don't know about demons (huh... that might be kinda interesting), except that it seems he very *specifically* forgot anything about monsters, himself, his family.
It was very good to see Dean remembering how to deal with the shadow demons...