I keep seeing these dramatic before-and-after photos on Pinterest that show how you can defog old plastic headlight covers using cheap toothpaste.
I was pretty sure this was crap the first time I read it, but I figured it was worth a try, since the headlights on the Dreamcar were covered with black walnut sap, the plastic was yellowed, I’d gotten overspray on them after forgetting to mask them off last time I painted the hood, and toothpaste costs a dollar a tube. If it didn’t work, I was going to have to replace them anyway, so why not give it a try?

Following several sets of instructions I found online, I applied some Ultra-Brite toothpaste to the headlights with an old toothbrush.


I scrubbed it around with the toothbrush for several minutes and then hosed it off. The sap came off, but the plastic still looked pretty bad, so I took some advice I found on another how-to-clean-your-headlights post and reapplied the toothpaste, using a Scotch-Brite pad to scrub it off.
When I rinsed, it looked pretty good — not perfect, but less yellow, maybe, and most of the overspray came off — but as the water dried, the plastic fogged back up and looked worse than it had to start with:

Back to Pinterest. A commenter on one of the how-to articles I’d found suggested applying olive oil. Another suggested vinegar. I’d made a pretty effective furniture polish out of a mixture of the two and still had some left under the sink, so I ran in and got it. Definitely an improvement:

Another commenter said the best method was to attach an old sock to a belt sander, put the toothpaste on it, and use it to buff out the scratches. Several commenters agreed with this, so I found a worn-out running sock and gave it a go.

Buffing seemed to help some, and I suspect if I’d done it first — before I took out after the plastic with that abrasive Scotch-Brite pad — it would have helped more, but I was still underwhelmed.
Yet another commenter insisted WD-40 is the way to go. Well, of course. Anything that can’t be fixed with WD-40 or duct tape belongs in the trash. I rummaged around under the kitchen sink, found my WD-40, and applied it, buffing it in with a fresh sock on the sander.
This was the result:

Not bad at first glance. Maybe an improvement. But as soon as it rained, they fogged up again and looked like frosted glass in the dark — very pretty, but I’m not sure you’re supposed to drive with a Streisand filter* over your headlights.
Conclusion: This method is, indeed, utter crap. The sock on a sander might work without any of the substances I applied, but the toothpaste and Scotch-Brite just scratched up the plastic and made it worse. I’d also be leery of using anything abrasive or acidic near a factory paint job, as I’m not sure what it would do to the finish.
Pinterest fail. I’ll take the Dreamcar to the Honda dealership next weekend.
Emily
*My friend Brandey’s term. We used to watch a lot of old Barbra Streisand movies, and Brandey noticed the cinematographers always used a soft camera filter on her close-ups.
I’ve heard bug spray works, but haven’t tried it. Also heard Pledge furniture polish. There’s a guy here in town that does them for about $30 and guarantees his work.
I hesitated on the bug spray because I’ve heard it melts the plastic and makes it worse. I tried it this morning, since they’re shot anyway; results looked about like the WD-40. I’m guessing it’ll fog again with the first good rain.