Why do Stanford math professors still use chalk? (2021)

> Conrad also pointed out that if one accidentally applies permanent markers on a whiteboard, then the board would be “instantly dead,” a nightmare not applicable to chalkboards.

Not so.

Like dissolves like. You take a dry-erase marker and over-write the permanent, and then wipe both off.

I started to use water soluble crayons (stabilo woody) for my whiteboards and they are great.

The only small drawback is that you cannot easily correct by erasing with your finger (possible but you need to insist)