repair or replacement of 41c clear display cover

[Hans Brueggemann]

the protective window seems to be mold-infested from the inside.
if your soldering skills and your soldering equipment are up to it, it's not that difficult to desolder the LCD from the main board. desolder the mainboard side of the contact strips only, not the LCD side, because the brown LCD circuit board is made of thermally inferior material and notorious for "losing pads".
once the LCD assembly is out, a couple of cotton swaps and acrylic polish on the protective window in the calculator top frame will do the trick.
the LCD assembly itself shouldn't be polished. use isopropanol (IPA) and a cotton swap to wipe its display surface clean. use sparingly, don't let the IPA trickle into the contact stripe area.