No wonder Apple switched to aluminum cases. In a hundred years, the computers will be as shinny metalic as the day they were made. But what to do about a vintage Apple Lisa, or Mac 512K that is in perfect, clean condition but... Yellow-Brown yuk colored? 1) Why do some macs remain perfectly white - grey and others turn yellow brown? 2) The plastic seems rotten to the core. That is, there are no layers of yellow to remove. Any plastics engineers lurking out there?