The existing nut was filed out for larger strings at one point, so I popped that off as well. Scored it with a razor, and used a paint stick tapped with a hammer as Kira suggested.
As long as I was that far, decided I might as well do the Zymol/ScratchX treatment thoroughly documented by Paul. Stripped 'er down to the bone. All that's left are the truss rods and frets. All I can saw is WOW! The wood has a new found depth and richness! This baby is fit for MOMA in NYC. It was in pretty decent condition to begin with, or so I thought. But I was truly amazed with the Treatment. But a caveat, it is really slippery now. Gotta be careful with it. I wore cotton gloves during the final polishing. And a nice benefit is now my studio smells like a woman's volleyball tournament at East Beach in Santa Barbara.
Yours looks a bit dry. 
