The ancients were pretty efficient in recycling some things -- the Archimedes palimpest comes to mind. I think that some of the Roman era coffins were made out of this kind of papier mache' material. They're beautifully painted and gilded, but not as sturdy as a wood or stone coffin.

And, of course, these coffins were only for the middle class and upper class. The poor fared worse in these matters.