An acetone bath may help. Looks like it took a hit at about 7-8 o'clock on reverse rim? At this point, I would say it is in low mint state and valued as such for a standard 1967 half.
Did you pull it out of a '67 holder? I need to find mine and make sure it isn't aging badly.
"Nummi rari mira sunt, si sumptus ferre potes." - Christophorus filius Scotiae
























