I loved this article on making paper for U.S. currency, which is produced by one company out of cotton and linen. Up until very recently, the company used denim as a source of raw material.

> "But recently, Americans decided they liked jeans that stretched, so jeans companies began adding spandex to their fabric. Money with spandex in it wouldn't be money anymore, which means much of Crane's time is now spent on a global search for waste cotton that wasn't used to make elastic pants."

http://www.esquire.com/news-politics/a24292/benjamin-hundred...