i used Meguiar's Ultimate Plastic Restorer on my old car back in high school, and it took care of the Zymol wax that I accidentally got on some trim.
Meguiar's G15812 Ultimate Black Plastic Restorer : Amazon.com : Automotive
Also, I used Zaino on my previous black Porsche Cayman, and oh man did it shine! I have used Mothers, Meguiars, Zymol, and Klasse. None of them compared to Zaino in protection, shine, and wet-look. What's even better is it doesn't require serious elbow grease to apply nor do you need to buff it out, which would save you soooo much time on that big ass truck!
Edit: Forgot to mention - what got me started on ranting about how great Zaino is is that it does NOT make nasty white marks or fade the plastic pieces. You can wipe it on literally everything - glass, plastic, metal - and it will not deface it. Just saying it's great stuff, and you should check it out on their website.