The DU Lounge

I once had to remove some dry marker writing that had been left to "set" on a whiteboard for months and didn't rub off with the usual cleaner. After testing various cleaners on out-of-the-way corners, I found toluene (try your hardware store -- FLAMMABLE, AVOID INHALING FUMES) did a good job of removing part of it. IIRC, all the green and blue ink came right off; the black ink (which is really a mixture) got leached of its green color and left red ink behind. No amount of wiping with toluene (or acetone, or alcohol) would remove the red ink -- but warm water did ! From that point on, I alternated toluene and water and got the last traces off (IIRC).

Don't use something like toluene, or worse, "Goo-Gone" without REALLY good ventilation. Goo-Gone should really only be used outdoors or in a hood, and you should wear gloves when you use it.