
Down Corning #4, electrical insulating compound. Great stuff, we use it onboard ship to keep the rubber boots on our shore connections from drying out and some people on the forum have used it to rejuvenate the rubber window seals on their buses.
It turns out that it works equally well to repair sun damage on the plastic trim pieces on the inside of the van! I did my window frame pieces and on the lower half of my shifter.
You can see before here,

and after8-) :

I just put on a pair of latex gloves, put a bit of #4 on my fingers and massaged it into the plastic. Any excess you wipe off so it isn't greasy. easy Peasy!
