Removing internal AR coating?

I picked up a Dynamic III with damaged internal AR coating. I ordered a replacement crystal from TMWatch (his repro, no AR), but it is lacking the detail of the original, so I was thinking I could just remove the original AR coating.

IS there anything I can do to remove it chemically that won't damage the crystal? Or perhaps pretty easily? Crystal is out of the case.

Ah, thanks! Not sure how I missed that!

I spend a bit of time with polywatch and a cloth but it looks like I just needed more elbow grease 😁

I think I have some diamond paste somewhere too, maybe I'll give that a go.

Was really hoping there was a simple chemical solvant that would work, much lower effort and risk of screwing it up 😁

Thanks!

Welp, my attempt went.... 'eh'. 80k diamond paste that I had barely did anything to the AR coating other than the ocassional scratch through. SO I switched to the 30k (my next lowest). I went a while, and it LOOKS like I'm getting some progress, it is SUPER slow going. The missing zones are getting bigger, but not at any reasonable pace. AND I'm afraid to go down to 10k.

SO, I decided that the TMWatch version, despite not being 'rounded over' (its just a normal sapphire crystal), is nice enough.

I picked this up with the missing AR on the inside of the crystal, and low enough amplitude that it 'often' stopped at 1145pm for the previous owner. I'm not the first watchmaker in this (the hour hand has some missing paint near the center, plus some other obvious issues, like the black grease EVERYWHERE), but I got this one running quite nice!

Included is a photo of the mainspring, which is FAAAR from flat for some reason. Guess the last guy didn't replace it😁