Presenting: Armour Etch. Bought for around $10 3 oz. from Ebay.
Noted for Plastic eye glasses only as claimed on many websites, although I'm not sure why (I applied the cream to a glass edge of a table surface and it seems to leave quite a permanent stain)
Very effective indeed. Applied Armour Etch Cream (originally purposed for glass stenciling) on both sides of my coating-corroded eye glasses (I was quite sure it was made of plastic and not glass) for about 60 seconds, rinsed with running cold running water and voila! all those scratches I thought was permanent were gone. Of course, these are scratches on the coating layer, not the plastic pieces.
Armour Etch works by removing the coating layer. I gave some thought before going through this process. I gathered the purple-like coating wasn't too important. I believe it's AR coating or Anti-Reflective coating. I'd rather go with some increased reflection (I don't see much difference after the removal of the coating), than enduring seeing through those scratches. Getting another set would cost me and doesn't seem worth it when the coating could easily be scratched again.
Now I see things so clearly I couldn't believe I have forgotten how much I've missed all these time. Including the left-clear right-blurry effect that was intentionally designed by my optometrist to improve my right eye. Let's hope my right eye starts to improve again.
This is the only eye glasses I've bought since 97, and thus the only one I've gotten in the States.