Why shouldnt you open an Etch-a-sketch?

Answer 1

Etch a sketches have little particles in them that cover the screen (they get pushed off when you turn the dials and draw a picture) and if you opened it they would get in your eyes if you weren't careful, and they would make a mess.

Answer 2

The "Etch a Sketch" contains Mercury and mercury can be poisonous (the methylated oxides are really dangerous).

Another answer:

Nonsense. The Etch-A-Sketch does not contain any form of mercury and never has.

It contains aluminum powder and polystyrene beads. If you crack the case, humidity will get in and it won't work properly. If the contents are spilled, the dust spreads by contact, so it tends to go everywhere and is difficult to clean up. While aluminum has extremely low toxicity, it has no function in Biology so it's common sense that it is not a good idea to eat a lot of aluminum powder. It's definitely not healthy to inhale the stuff.