More to explore:
recycled book page envelopes (these would look cool made with comic book pages for superhero party invites or with sheet music for a rockstar party)
vintage recycled book envelopes from readwritebooks on Etsy
Old book pages become envelopes. Take apart an envelope carefully to make your #Greeting Cards| http://greeting-cards-46.blogspot.com
envelopes made from old book pages or sheet music.