Interesting thread...
About 18 years ago, the electrical contractor that installed power in my townhome were kind enough to buy me replacement panels for my SL3's and Aerius'es (courtesy of a cable guy's shot shovel, aluminum 110V legs into my house and a distinct lack of conduit)... the explosion on a lazy, rainy Sunday and totally vaporized aluminum was an interesting experience!
Anyways, I called ML to ask advice, and I think it was Jim (might have been Ron... this is back in2002) who was telling me that before I swapped the new panels in, I should take the old panels (they were arcing a bit), put them in my bathtub, and pour distilled water over them... A lot of distilled water! Let them dry, and try 'em out.
Well, I've had the spare Aerius & SL3 panels in the original shipping boxed in my (slightly environmentally controlled) garage ever since!
Might have a look at them to check if they've turned to dust! Oh, hang on... it's 2020... they might have been posessed by Amun-Ra, or some such!
Russ