Most parents can remember the unkillable piles of wast-paper which start growing around tables and chairs, even stairs, as soon as a child reaches the age of three and learns how to wield a crayon.
As the child grows, so does its self-esteem, and the artwork shares its new-found value. Suddenly
the drawings are precious, and un-discardable. Every trip to the recycling bin is followed with bloodcurling screams if any of the masterworks so much as take a peek out.
I propose an extremely light sensitive drawing paper (sold in a dispenser) which will disintagrate to a vacumm-uppable dust after a day or so of enjoyment. It would also be usefull for people who sketch too much, (like me) or for secret documents (limited viewing time).
<sorry, this idea has already been mostly baked, it seems.>