If its the black plastic, like around the mirrors or the wiper-cowl try peanut butter. Sounds way off the wall, I know I thought so to until as a last resort I tried it and it worked. I used it on the sail panels, so I was able to take them off and go to the kitchen sink to apply and rinse.
For my weatherstripping/ rubber, I use the Meguiars interior cleaner that comes in a bottle that you could mistake for Quick-Detailer.
