What to use on headlights and tail lights?
 

I was going to try Meguiar's Headlight Protectant, but apparently it's not very good. Is it safe to use Carnauba wax on the plastic headlights? I have Meguiar's Gold Class wax.

Pure carnauba wax should be fine, that's what I use on mine - just don't use anything even mildly abrasive (like a cleaner-wax). The plastic typically has a finish on it to minimize UV damage and you don't want to remove it. Be careful, clean off anything (bug debris, etc.) that could scratch the plastic first by softening it and wiping it off with detailer and use soft microfiber cloths with a gentle touch.

If you really want to protect the headlights from damage, look into installing a protective film. There are threads on here about it and it shouldn't be difficult to do on just the lights.

If you have an optimum polymer technology professional near you, get him to install opti-lens. It's a lifetime protectant with high uv protection based off the world famous opti coat.

Wax is going to be fine for any smooth surface. Carnuba has very poor longevity however, so just be aware.

carnauba wax is fine

polymer sealant is better

Not tried the Optimum Lense protectant but I've been applying Opt-Coat to my clients headlights for a couple years now with great results.