From the new scientist back page:

Battery brainwave
IT SEEMS such a waste to throw away a battery because a digital camera
cannot draw enough power to light up the LCD screen, when you know there is
still some juice left in it to do...something. A UK company, SnailAway,
reckons it has found that use: most discarded batteries can still give a
snail or slug a small shock. Connect one to a closely spaced pair of bare
wires, and any slug or snail crossing the electric fence will bridge the gap
with its wet slimy body, feel the volts and turn tail.
You are spared the guilt of waste, the plants are spared slugs, and
hedgehogs are spared lethal slug-poison.

( http://www.newscientist.com/backpage...mg18625051.800 )

Bob