>I finally got around to replacing the batteries on my TRS-80 PC-1 and >noticed that the intervening years have not been kind to the LCD >screen. It appears that there is liquid crystal leaking out under the >polarizing screen, creating what looks like black smudges on the >display.

I don't think there's anything you can do about them. I noticed that all the PC-1s that I saw were developing that problem and that was probably over ten years ago. Radio Shack Quality!