Cleaning (yellowed) outside plastics.

Try ' astonish ' cream/paste, available from 'The Range' or B&M £1:00 tub

Or MR Muscle kitchen an bathroom cleaner and a washing up scourer you know the one with the  plastic scourer one side and sponge the other, brought mine up a treat..

Please let me know how you get on!

I have some quite yellowed trim on mine in places. As yet I have done nothing about it, as my first job was at a white pigment manufacturer and I know from the plastics grades we use to make that if the coatings were not spot on, there was a photo catalytic reaction from the pigment that would yellow the plastic (other companies had previously been sued by the likes of window frame manufacturers for excessive yellowing).

I had therefore assumed the yellowing was down to poor manufacturing / materials / photo catalytic breakdown and was not just a surface issue, but throughout the plastic where light had penetrated.

try toothpaste rubbed in with a damp cloth. Or, go onto YouTube and search for "cleaning yellowed plastics"