Pilot Frixion erasable pens
There's a wealth of office supplies invented in Japan that can make your day-to-day quite a lot easier. Here's TechRepublic's roundup of 10 Japanese office products you didn't know you need.
Erasable pen technology has advanced significantly since the terrible smudge-fest of the first generation erasable pens from the 1980s. Pilot's Frixion line of erasable pens and highlighters use a type of ink which disappears with heat generated from the friction of the included silicone eraser.
Granted, the use of heat to make the ink disappear makes it a bad idea to leave your notes in a hot car, though your writing will reappear if you put your notebook in the freezer.
Pilot Frixion pens are officially sold outside Japan. They are available from Amazon and office supply stores.