This is a very small repayment against what I have gained from this board.
Below is a pic of my DMM displays after I polished out the covers. Watchmakers use Polywatch to remove scratches from watch crystals.
I clean it up with the cloth, then use IPA or eyeglass cleaner, and then wipe off any streaks with Kimwipes.
Deep scratches have to be removed with a polishing wheel, but you need a plastic cutting compound and have to be careful to avoid distortion or burns.
Here is a link to the product on Amazon: (I hope).
https://tiny.cc/bmievzRegards,
Dewey