Clean label residue from mask lens?

[Belmont]

I used the burning method on a brand new mask and it worked fine. After that I tried it on my old well worn Scubapro frameless. The flame revealed a circular shape on each side of the lens.
I figure it is the mark left by suction cups used in the manufacturing process.

I was surprised to see that there was something left on the glass after many tooth paste scrubbings, defog applications and spit.

I remember from my chemistry lab classes that we had to clean our glass tubes with picric acid to remove every contaminant and even oxygen molecules on the glass that would ruin our experiment.

Anyone here knows if it could be used for masks?

I checked on Wikipedia and saw that the picric acid we used then is listed as an explosive :11:. Is it still used, even in labs???

 

[chewslife2]

Hmmm!
I bought an atomic sub-frame and when I was cleaning it the first time I kept seeing the imprint of the plastic static label on the glass also and i scrubbed with soft scrub and toothpaste and every time I rinsed I could still see the imprint, I wasn't sure about how the burn method would react with the ARC coating so I was letting it sit whilst I looked for another answer.After a couple a days I just rinsed it again and the imprint is gone, could be the static charge on the glass takes a while to disipitate. But then again the 60's were real hard on me, so who knows.

 

[redacted]

I'll give the goof-off/WD-40 a try. I'll save the burning as a last resort, the mask is pretty expensive and I don't want to accidently burn the skirt.
I

I don't think I'd resort to the flame. If the solvent does not remove it AND if it interferes with vision, I think I take it back to the Atomic dealer for resolution.