Hey, thanks for another reply.
I've been thinking about this, and I'm not sure it'll be much help. Glass is a good insulator, so even tapping one side of the tube won't affect a huge area. I don't *think* it'll hurt anything, because the front of the tube isn't directly connected to anything else or it wouldn't be building up the static. (Though being an insulator, it wouldn't matter if there *was* something connected to it.) There also won't be much charge there, but static does get to really high voltages. And the dag on that tube, and the grounding wire, is probably at earth potential already. Certainly it would be on a PVM/BVM. And the tube is already pretty close to that.
I guess it might do something bad to the grille/mask (I'm not sure what that set uses) but I wouldn't think so.
Where are the sparks going, exactly? How did this anti-static coating work?
If you google CRT anti-static coating, you can find lots of patents related to it. Here's one.
I think it's just an extremely thin, transparent layer of conductive particles.
Interestingly, the sparks I'm getting like to go to a bit of the coating on the very edge that I haven't polished out yet. At least, I think that's what's happening. It probably makes its way back to ground through there. What will happen if I ever truly eliminate the pathway out, I can't say. The mask around the screen seems to be plastic.
The sparks are large and loud - usually just one happens per power-up or power-down. I wouldn't want one to hit me, or any sensitive equipment.
I haven't had time to mess with it, but assuming that the metal case itself is grounded, it would be very easy to run a wire from one of the screws to the front of the screen. If it won't hurt anything to discharge the static that way, I might leave it there for peace of mind.