So - after an hour of cleaning, sanding, wetsanding with oil, steel wool with oil, and buffing, I got it looking better. Still got a huge light area on the high strings:
![Image](http://i.imgur.com/VQyZjxW.jpg)
Overall, the dusty look is almost gone. It's still covered in file marks (you can see the high E edge looks like it's been chewed) but I tidied up the frets and it looks OK from a few feet away:
![Image](http://i.imgur.com/k5y6daM.jpg)
Ironically I oiled the XII fretboard as well, and it did almost nothing!
XII is a knockout to play, a bit harsh in the pickups, and the Jag is pretty excellent with a similar glare, I don't know how a neck pickup can sound bright but it does. Might change pots, might use the ... <checks notes> ... "tone" control.