Disappearing ink to boost paper recycling [New Scientist]: Toshiba’s erasable ink can be used in ordinary laser jet printers and
pens. A printed sheet is wiped clean by passing it through an erasing
machine. The “decolourable” ink, which has been tinted blue to help
distinguish it from ordinary, non-erasable, ink, has been named
Downside, for the moment: pricey “erasing machine,” and 2 hours to
erase 200 pages. But both those downsides should be only temporary.