sure do, Stik,,,,,,,,the pretty "yellow decal surround" on the Phantom Demo Bomber I posted is the reason I used such a small pic, lol, that was a Testors Gloss, decal, then Testors Gloss build
that staining, and the old Poly S "peeling problem" are the two main things that made me move "into the 90s" and use Future and Tamiya Flat Base concoctions,,,,,,,,,I wish I was smart enough to do one of each side by side back then,,,,,,I'd have a benchmark to show the difference when a new person asks about yellowing
and yes, I've also read that it's "all caused by nicotine",,,,,,,but, mine stained in my non smoking house,,,,,,after about,,,,,,,,,ohh,,,,only 15 years or so (the model is older than Miss Owl)
it's hard to build a collection when you have to "discard and replace" every decade or so,,,,,,,,,,,I think I have the technology and chemistry figured out now, though,,,,,,,,,,,I sure hope so, anyway,,,,,,,gettting to be too old a dog to keep learning new tricks
Rex