No - many are coated both sides. For removing outer AR coating I use diamond paste - fine so 0.5 or 1 micron will do the job with just dabbing a bit on the crystal and rubbing it with your finger. i just use a generic "polycarbonate headlight polisher" from pep boys or so - I had sitting around in the garage ... works just as fine ... never had a scratch that I couldnt get rid of

I believe that AR coatings are only applied to the inside of the watch crystal. If this is the case, then the scratches you are seeing are not to the coating, but to the sapphire itself. Sapphire is incredibly hard to scratch (bravo for finding a way to scratch it), but that also means it is equally as hard to polish.I will sometimes, depending on the watch, use a coarse as 400 grit to start - all done by hand and you do need to be careful not to overdo it. It looks worse before it looks better:

When you are done and start seeing results, wipe off any residue from the crystal. You can do this with a clean cloth. As with all polishing, move through grits from coarse to fine, making sure that you remove all of the previous marks before moving on, and finished with Polywatch. Please excuse the dust... Polywatch® Glass Polish. High Tech Scratch Remover For Glass. Repair rather than replacing. Removes fine, light and medium deep scratches from watch glasses. Sufficient for approx. 30-40 applications. For use on cars, smartphones, watches, furniture, household, hobby, windows etc. What I do is use microsandpaper, starting with 1800 grit and working to 12,000 grit, this allows me to remove virtually all the scracthes, as a final step, I use Polywatch.Polywatch is for removing fine scratches so the scratches have to be minor, or it's used as a final polish. Trying to remove large/deep scratches with it is not really the proper use. If the scratches are deep enough, you will just make them shiny rather then remove them. Using Polywatch on this for example, would be mostly useless: not to diss polywatch ... but I bought a bottle of "generic poly carbonate headlight polish" ... big ass bottle for 0.99 ... its the same - works the same I owned the same type watch years ago. I had same issues. I polished off AR coating with Polywatch, and it took a great amount of time and effort. I believe there should be a post/thread on this topic, specifically for PO. old t-shirt .... moisten lightly with some finger's worth of water until it results in a "wet-spot" (insert dirty joke here) ... then a bit of the polish (fingernail sized drop) ... then I gently work the mustardy-paste into the wet spot until all the excess is in the fabric (about 2-3" across).

Plastic watch glasses scratch very easily and replacement is not always possible, particularly where the case is plastic. Polywatch slightly disolves and grinds down the surface of the plastic watchglass to smooth the edges of the scratch and fill the gaps with dissolved material.I have lenses scratched by my glasses. Both in the upper middle of the lens. You mention blur... and VR headsets are already blurry. Will using this just cause worse blur so that trying to look through the scratches might be better?

The short answer is that yes, Polywatch works to remove scratches from watch crystals. Note, however, that this only applies to watch crystals made of plastic, hesalite, or acrylic. Polywatch will not work on sapphire or glass crystals as the abrasive material is not able to grind down the glass as it can with plastic. If you use Polywatch on glass crystals, it can instead cause scratches. How does PolyWatch work?Polywatch alone does remove the tiny scratches and gives a nice overall finish, sort of like a coat of wax on a car finish. Usually I use masking tape around the bezel and edges to protect them. This is very important for gold-plated or filled watches as the chemicals tend to get underneath the plating and react with the base metal of the case. With the included polishing cloth, rub in a circular motion, with firm, constant pressure. The heat from the friction will allow the Polywatch to smooth out the crystal's surface.