I have peeled the frosted faceplate off 3 tubes so far using a Burnz-O-Matic torch and alot of patience. The bonding material is the same that is used to laminate automotive windshields and becomes fluid at 350 degrees F, it delaminates around 200 degrees and has insulating properties with respect to heat meaning the tube face itself won't get very hot.
I just heat the entire faceplate up slowly going in a circular pattern to even out expansion and after a while the the faceplate will break loose around the corners, just keep going in this manner for a while and eventually it will fall off. Do position the tube horizontally and support the neck and bell with cat litter bags or something soft and do use a heavy blanket over the bell just for safety. I wear my welding aprons that are leather and also wear my welding helmet with clear faceplates, Im a bit paranoid. Also don't forget to carefully slit the clear tape around the perimeter that covers the bonding resin, I got tricked once from the tape.

So far done 22JP22, 25XP22 and 20 something 22 in a zenith metal.

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