I've always believed it was a local newspaper headline from the 60s or thereabouts. Google isn't helpful: lots of references to its use, but the only actual source given is Private Eye in 2004. Given it's referred to in a 2002 Guardian article on headlines, and I think I first heard about it in a school English lesson in the late 80s or very early 90s, all we can say is that recycling's a good thing!
