looks like it's gonna be quite an adventure...
perhaps I should just paint the whole room black and pretend it's always been like that.
but hey, thanks for all the suggestions, keep 'em coming
a good eraser does seem to produce decent results (at least to get it in an adequate condition for a repaint) but it takes like half an hour to erase a few inches... so if I start working on it now, maybe I'll be done by the end of the semester.