303 Aerospace Protectant is great stuff. A bit pricey, but it does SO much, and protects so well, that it's worth every penny. You can get it by the gallon at West Marine, Camping World, et cetera. It's not petro-based, so it never feels oily or greasy. Anything subject to sun damage, direct or not, is a target. The only place you DON'T want to spray it is on floors or places you directly step, as it is SLIPPERY, even if not greasy. I douse my tire sidewalls with it, all rubber weatherstripping, dashboard, all interior vinyl and plastic, etc etc.
Along with WD-40, and Duct Tape, it's an indispensable item in the 21st Century.