Refinishing/cleaning stained plastic surface

Any chlorinated solvent will do (automotive brake cleaner).

You might find that the chemicals have actually changed the plastic's make-up somehow. This often alters the colour and cleaning alone will not undo the change so unless you are up for a complete re-finish, you will have to live with it I am afraid.

Repaint is an option but choose a paint that is food grade safe and has a low VOC number so that it does not leave such a chemically unpleasant smell. Also consider that you might chop food on the surface so you would not want bits of chipped paint in your food.

Maybe a veneer top is the best option as most artificial worktops are veneered anyway. You can get nice marble or granite lookalike veneers nowadays.

Have you tried laying paper towels saturated with bleach over the stain? If kept damp overnight it might dilute the stain away.

Peroxide or Oxy Clean may be better than chlorinated bleach.

Call it art and be proud of it.

Hi. I'M Billy Mays. Billy Mays here for Oxy-Clean...................

I have removed same from acrylic fabrics with the NAPA brand carburetor cleaner 'Gum out' but don't set more than three seconds or it may remove more than you want it to.