...actually the discussion was about removing cigarette burns from chips. That's where the history of the chip notion was coined. The guy with the sandpaper started dragging around the red herring that nits were claiming "dirt is history" so's you wouldn't notice him fiddling about. The Dirt Is History boogyman is urban legend. Adding or removing material from historic artifacts is not, unfortunately. That's my story and I'm stickin' to it!