Here is a great article on 10 things that you can do with dry-erase markers. I mean, hey. Just using them to play hangman at work would be boring, right? You don’t do that. Crap.

From the article:

Remove permanent marker The solvent in dry-erase markers will dissolve many permanent marker inks — just scribble over the permanent mark and wipe away with a paper towel. You may have to do this more than once to clean it off entirely.

Link