competition: Best way of cheating at school...

Pencils/Erasers are generally allowed during exams.

I used to write stuff inside the paper around staedtler erasers. Remove it from the eraser, read what you need and put it back. You can also write directly on the eraser and make it diseappear by rubbing it with your thumb.

You can also put a small piece of paper in a mechanical pencil, opaque please