I can tell you that the plastic turned a very deep amber color at 350, like a deep beer bottle brown with a prominent red hue to it. IDK if that helps us identify the plastic.
I think you are right about the screen itself cracking. After looking at it very closely, I noticed a 1/2 dollar sized region in the perfect center of the screen that had cracked. The crack(s) weren't visible, so it may have been a very fine crack, or a series of very small cracks, but either way, the liquid crystal escaped from that area.
Ah, see, I figured you'd need to boil the water out. Guess not...
Okay. If the next one is contaminated as well, we will try a lower temp, for a longer period of time. Something in the 180-190 region with examination every 15 minutes for at least an hour or two, longer if the screen doesn't appear to become perverted in any way.
If anyone else has any screens that are terminal, feel free to contribute to our process here as we work to hammer out the exact temp and duration necessary to fix this problem without damage to the screen itself. If you don't want to try it, I'm happy to accept screens and do it, in the name of science!
I have no idea what the lowest setting is, I'll have to check, I've never used it that low.
Another bit of info, at least at the higher temperature, it STINKS! I had to turn my exhaust fan on. It smelled like overcooked adhesive and plastic (no surprise, really)