Eros chair for Kartell cleaning  

@hotdogbathtub, Not expert on these, but you should find a retaining clip underside of the base which, once removed, will free the seat/spindle assembly. If you are lucky, how to remove the seat from the spindle will become obvious or unnecessary at this point. If not, try carefully prying off the central metal cap that may cover a fastener.

I do have enough experience polishing plastics to recommend reading up on polishing polycarbonate (seat material for Eros) as the protocol differs from that for polishing acrylics (Perspex, Plexiglas, etc).

Cool chair. I kinda like the patina and would, if mine, try doing a light-handed cleaning/buffing on the plastic and leave the rest more or less as is.

Best of luck!