said by tired_runner:So the Palmolive is accelerating the oxidation and there's no turning back at this point? Or will using a car wash liquid help mitigate?
I would say that is nonsense. I haven't seen pics of the car, but the parts (plastic) you are talking about is normal after 15 years (you said it was a 98).
The parts that deteriorate first would be flat (horizontal surfaces) and the plastic painted parts just due to the difference in properties between plastic VS. metal, and VS. time (weathering).
Polishing (when you buy and do a polish before waxing) is made to remove a few microns of the clear coat, this could be all you need to make it "look" rejuvenated.
Just like what this topic is about, headlights (and the minor abrasive sanding required to fix it), paint is the same after time, 15 years in your case.
To say Palmolive did it is nonsense.