Ouch. At least it's still recognizable, unlike the Barn Grime Apple II (episode #180).
I think that Extended Keyboard should get a Purple Heart or something. :-( Those poor keyswitches!
Let us know how it goes. :) And congrats on your new(?) Duos, too!
Yeah, I'm guessing it probably sat directly under a fluorescent light or something. I just love the seller's description: "Yellowing of white plastic case with age which is pretty normal on older Macs from the 1990's."