I find that by using the mouthpiece on the O2ptimask and removing it every time I exhale, I don't have to clean things near as often as I used to (except the mouthpiece itself, that is).
If there were a way to easily remove this scuba demand valve between each breath - in other words, have a mouthpiece that didn't have a part that has to fit between your teeth and the insides of your lips - it would be the katz sass.