Originally Posted by Duke-TJ
On my exterior black plastic I use a paint additive you can buy at Home Depot called "Penetrol". Lasts about a year for me. Must apply carefully to avoid glass/paint. No more wiping on stuff that only lasts a few days. I haven't tried Adam's stuff for this since I'm happy with the Penetrol.
Wow, I've never heard of using Penetrol. Sounds like a good option, but scary if it's damaging to paint. I may give it a whirl if nothing else works.
Somebody recommended 303 Aerospace Protectant. Supposedly it has an SPF40 UV protectant as well. "Protects & Instantly Beautifies: Vinyl, Rubber, Plastic, Leather, Fiberglass, Carbon Fiber, Matte Finishes."
I may give that stuff a try, too. Sounds like it works great on boats even.