Oops! You wrote on a whiteboard with a permanent marker!

Problem

You picked up a marker and wrote on the board. When somebody tried to wipe it off with the eraser, no luck.

Answer

A permanent marker can be erased with alcohol, any alcohol, cleaners containing alcohol, failing all else, if you are near a bar, spirits such as vodka - but vodka is expensive so that's a waste.

I learned this years ago. I had written on a whiteboard which turned out to be the personal property of the previous speaker which he had left on stage.

My saviour was a lad who had just left a local college. He said, "Happens all the time at my college. You just need alcohol."