polishing rocker cover

[jamegumb]

I have a 1998 1.6 8v 6n and the rocker cover is a nasty yellow colour that these engines seem to go when theyve done a few miles. My question is: Does anyone know the corrct way to recondition / polish one? I had a quick go with some sandpaper and it seemed to come up alright, but im not sure whether you can do it with the rocker cover still on the car or does it need to be removed? Thanks Guys ) and Gals (