Press n seal is sort of like saran wrap (plastic film that is "supposed" to stick to bowls etc to cover food in the fridge etc, this PNS actaully sitcks to pretty much anything, you just press and away you go. you can seal it to itself (so you can put your sandwich in it if you want ) it is good for all sorts of things,
http://www.glad.com/plasticwrap/pressnseal.php
has a link that tells some ways to use it.