Toothpaste cleans because it is abrasive. It act likes sand paper. Yes it removes dirt snd grime but also removes some of your iBooks plastic. I guess it would be okay on the case... but I would not use it on the keys (unless you like to guess what key you are hitting) or you screen (very expensive to replace). If I was going to cheap about it, I would just use the moist cloth that apple recommends. If it is really soiled pick up some electronics cleaner (I use iKlear).