On 7/16/2017 9:09 PM, Danny D. wrote:
On Sun, 16 Jul 2017 20:40:23 -0400, Frank wrote:

Problem is not just oxidation but erosion by particulates like sand.

I read all the pages I referenced where I find it hard to believe the
lenses were 'sandblasted'. These look "foggy" and "yellowed" and "cloudy"
but they're not sandblasted, and, for passenger vehicles in suburbia, I
can't fathom the 'erosion' argument.

That would depends on where suburbia is. In the snowbelt, the roads are
salted and sanded and that can have an effect. Obviously that is only a
prtion of the problem but look at windshields after 60,000 miles.




So I think this is only "sun" erosion, whether that's a chemical change in
the plastic (oxidation?) or if it's a physical effect (UV damage) I don't
know.

I'd bet on UV. It is not kind to plastics.



I don't see why anyone would want "scratch resistance" in a headlight which
isn't exposed to scratching in normal use (dust bowl in Kansas might be
different but this is suburbia).

So you drive under 25 mph on perfectly clean roads. No bugs, no grit.




Here's my gut feeling (which can be completely wrong - so that's why I
ask):

1. I don't think it's sandblasting that did it - I think it was the sun.
2. I don't know if it's a physical change or a chemical change (or both).
3. I suspect if there was a "sealant", Toyota would have used it.
4. I suspect, as stated, polishing is the way to go (but I'm unsure).
5. I don't know if liquid "de-oxidizers" (whatever that means) work.

1. Mostly sun but could be pitting too
2. I'd think both
3. Agree, unless it wears off over time
4. Agree.
5. Never heard of them



My leaning is toward a 1000 to 2000 grit wet abrasive plus wax when done,
but I don't know how long it will last nor how good it can get yet.

I'd guess "good enough" and a few years.