What needs to be removed to buff headlights?

On a gen 2? nothing
Just tape off the perimeter and machine polish it with a plastic polish and 1000rpm via rotary.
Would take less than a minute or two per side.

Lay some PPF film on top and it'll stay clear for a decade until the film starts to deteriorate.

 

Or you can spray them with DuPont urethane in the gray and red gallon container that cost about $200 and I'm sure there are others won't yellow for quite a while actually.

 

Ultra Violet sunlight degrades the plastic lens. Garage parking, parking pointing away from the sun or in the shade, all helps.

 

Yes, mainly the original microscopic clearcoat layer that protects the plastic lens from exactly this.
With age, the clearcoat fails/oxidizes.
Assuming it's the regular kind from the outside, machine polishing removes that layer of dead clearcoat. (might take some wetsanding)

 

The original Stanley headlights and tail lights have a nice thick lens It's no joke You can bake it and take it off and put in Mary Moto shutter type HID business and all that glue it back down buff everything out real nice and have a fairly decent set of headlights no kidding But if not just putting LED bulbs in and crank in the adjusters down about eight and a half half turns brings your cutoff in the view and then you set it on the garage door at the right height sheets run and done. But to get at the point there's a good bit amount to sand and clean up on the original factory headlights on replacements you'll sand right through the headlight

 

Sometimes a good wash, and maybe a very light polishing, even by hand, is all that is needed to clean up headlights. Always try that before proceeding to wet sanding.

The headlights on our 2007 have a lot of very small scratches and pits. If these are empty or full of dirt the headlights are pretty hazy. That's because a clear headlight is a headlight with a perfectly smooth surface, and any defects in that surface cause light to scatter. However, if the headlights are washed thoroughly and then coated with wax or Nu finish they are still serviceable. I prefer the latter, the former attracts dirt faster. This works because it restores a smooth surface, and wax and Nu finish have an index of refraction close to that of plastic. Filling defects with those materials greatly reduces light scattering. If necessary the depth of these defects can be reduced slightly by polishing lightly, also I think it helps get out the more stubborn contaminants which are stuck in the defects.

This is separate from the problem of the clear coat on the lens disintegrating. Once that starts flaking the only fix is to sand that material off, smooth with finer and finer sand paper, and then coat with something.

 

Excerpt from 3rd Gen North American Owner's Manual:



Similarly for Gen 2, page 384:

 

I would truly like to know how an inert substance like wax can damage a relatively robust and also inert material like clear coated polycarbonate. Or even polycarbonate alone. In terms of chemical compatibility:

Polycarbonate Chemical Compatibility Chart

paraffin is "A-Excellent", as is silicone. They don't list any other types of waxes. Of course strong organic solvents, strong acids and the like will chew up polycarbonate.

I suppose if the wax was mixed with a strong organic solvent, and it had separated, the solvent could damage the clear coat. Never heard of a wax with that composition though. However, I had that happen once with an old bottle of PlastX. Shook it up and the stuff that came out looked a little runny, but it was the right color. Turned out all the solids in that bottle had congealed into a mass and the only thing moving when it was shaken was the solvent. When it was applied to a headlight it did a job on the clear coat, which immediately became gummy. (This was on the wife's Accord. We still have it, and even though the clear coat was messed up, the headlights still have not yellowed in those areas.) The wax I use is just pure carnauba wax though, no solvents. Nu Finish contains "Stoddard solvent", but that is also rated "A-excellent" in the link above. Also Nu Finish is technically a polish and not a wax.

The only other thing that comes to mind is that dirt and grit can stick in wax and if a person was foolish enough to just rub the headlight hard without washing it off first that grit might scratch the surface. If that was what they were worrying about they should also say not to wax the paint, because the same thing would happen there. Hence clay bars, touch free car washes, and all of that.

 

First, I spray the headlights with Totally Awesome All-Purpose cleaner from the General Dollar store. Then I wash off the headlights with water. After that I wipe them down with rubbing alcohol and then polish them with a small Milwaukee polisher. After this they look like new.

I use FARECLA G360 Super Fast Compound for all my polishing.

 

Take it up with Toyota. All I know it’s a pretty adamant statement, from someone who ought to know. Whatever their reasoning, it’s not hard to follow.

 

Yes, there were unambiguous about it. Unfortunately their statement is pretty equivalent to "don't wash your car with water", that is, it is so outlandish it requires an explanation.