Well it's not just Amigas, a lot of other things turned yellow with
older plastics. Indoors and out.
It could be due to ultraviolet light or maybe carbon dioxide,
impurities or whatever.
Nowadays, modern plastic has a component called `LV' as usied in
Loreal LV anti-wrinkle cream.
:-D
LV stops plastic going yellow, possibly a UV reflector and I think
it's used in the Dreamcast as well as uPVC conservatories and gutters.
For some reason my A1200 hasn't gone yellow, but a PC tower I have
nearby for holding the drives has sort changed a different tone.
I wouldn't bleach anything because it might leave poisonous residues
behind and make the plastic brittle. And I don't think an acid bath is
good for Amigas either.
Best avoid kitchen cleaner though and clean with a warm flannel like
they give you in Indian restaurants!
:-D :-) :-D