Well, the report: I also bit the bullet and took the AR coating completely off. It came off relatively easy, which leads me to wonder whether this coating becomes less stable (and thus easier to remove) over time. Who cares, I hope to never have to find out again. Anyway, the result is great, crystal clean glass. The days are still pretty short here in Maine, so the lack of AR doesn't yet seem to bother me. Frankly, I agree with whoever noted another member who liked it better without the AR. I do too.
Anyway, thanks for the help, and I've learned a valuable lesson, and tips, for cleaning my next plasma...which won't be far off. Thanks all.