I've been leaving notes in my dd8 lunch for a couple of years now and she has started putting one in my lunch or dh's lunch on occasion. I keep them all in a little file. I found some at Toys R Us and somehwere else that are reusable with a plastic kind of coating one them. Moisture from her ice packs mess them up so if it's a reusable one, I put them in the snack size ziploc bag. I also use those little cards from stores that tie onto a package or the small card for showers and parties. they're about 50 cents each. I also keep cute sticky notes to use.