As it turns out, you can't repair a damaged light diffuser. When liquid enters the display, it doesn't just sit on the plastic sheets, it stains them and etches them with imprints of where the liquid travelled. It can't be cleaned. So, both of my spare LCD panels are useless!

I don't think this machine will be very useful without its LCD... I hate to say it, but this project's back on hold until I can find a donor unit to pull parts from again.