Had a great chance to try out some products yesterday at the Autopians GTG, and I've made a couple of brief remarks, but wanted to do a more organized report.
The plastic headlight covers on my Benz are a sort of "ribbed" plastic. They were horribly yellowed (I think Forrest said "oxidized"), and had very deep scratches/pits. Also realized that some things I thought were scratches are actually cracks that go all the way thru the lens cover.
I had bought the 3-pack "trial kit" of Novus 1, 2, and 3, and planned to tackle the lens covers with those. But the general consensus was that even Novus 3 wasn't aggressive enough.
Forrest shocked the heck outta me by handing me a jar of Mothers Mag & Aluminum Polish.
(Turned out he knew what he was doing, of course! 
) Under his guidance, I used the PC and Meguiars red pad. Slathered some Mag/Alum Polish on the lens cover, used the PC at a pretty slow speed (2-3). As Forrest warned me, 2 things to watch out for:
1. Don't use much pressure, or you could (a) cause more cracking and/or (b) cause heat build-up which would (of course) be an awful thing on plastic.
2. Keep feeling the plastic as you work, to be sure it's not getting warm.
Worked the polish a long time (maybe 5 mins?), stopping occasionally to wipe off, check results, then apply more polish and continue.
There was definite improvement in the "brightness" or clarity of the lens, the yellowness was virtually gone, and there was a dramatic improvement in the smoothness. So then I spritzed it with alcohol/water (not sure why, but Forrest told me to -- probably to clear off residue), and applied Mothers Plastic Polish. Mighty fine. So then I did the other lens using the same process.
Toward the end of the day, Mike demo'd Meguiar's PlastX and explained it has diminishing abrasives, so I grabbed it out of his hand and ran back to the lenses. Used it on one of them. As he had warned, it took an awful lot of elbow grease, and I worked it a long time by hand. It further improved the "brightness" and further reduced the scratches/pits.
Not sure exactly what my conclusions are, and I'm not exactly great at the "scientific method." In future, if normal plastic polishes don't do the trick, I expect I'll repeat pretty much what I did yesterday -- going on the "start with least abrasive product" principle: start with Mother's Mag/Aluminum polish, then move to the more aggressive PlastX. I think I can still get the lens covers smoother, so I expect to continue with the PlastX.
A caveat: Remember I was dealing with hard plastic (not something flexible like a convertible rear window), so I was able to use a fair bit of pressure with the PlastX.
Hope this is helpful to others.
The plastic headlight covers on my Benz are a sort of "ribbed" plastic. They were horribly yellowed (I think Forrest said "oxidized"), and had very deep scratches/pits. Also realized that some things I thought were scratches are actually cracks that go all the way thru the lens cover.
I had bought the 3-pack "trial kit" of Novus 1, 2, and 3, and planned to tackle the lens covers with those. But the general consensus was that even Novus 3 wasn't aggressive enough.
Forrest shocked the heck outta me by handing me a jar of Mothers Mag & Aluminum Polish.
(Turned out he knew what he was doing, of course! ) Under his guidance, I used the PC and Meguiars red pad. Slathered some Mag/Alum Polish on the lens cover, used the PC at a pretty slow speed (2-3). As Forrest warned me, 2 things to watch out for: 1. Don't use much pressure, or you could (a) cause more cracking and/or (b) cause heat build-up which would (of course) be an awful thing on plastic.
2. Keep feeling the plastic as you work, to be sure it's not getting warm.
Worked the polish a long time (maybe 5 mins?), stopping occasionally to wipe off, check results, then apply more polish and continue.
There was definite improvement in the "brightness" or clarity of the lens, the yellowness was virtually gone, and there was a dramatic improvement in the smoothness. So then I spritzed it with alcohol/water (not sure why, but Forrest told me to -- probably to clear off residue), and applied Mothers Plastic Polish. Mighty fine. So then I did the other lens using the same process.
Toward the end of the day, Mike demo'd Meguiar's PlastX and explained it has diminishing abrasives, so I grabbed it out of his hand and ran back to the lenses. Used it on one of them. As he had warned, it took an awful lot of elbow grease, and I worked it a long time by hand. It further improved the "brightness" and further reduced the scratches/pits.
Not sure exactly what my conclusions are, and I'm not exactly great at the "scientific method." In future, if normal plastic polishes don't do the trick, I expect I'll repeat pretty much what I did yesterday -- going on the "start with least abrasive product" principle: start with Mother's Mag/Aluminum polish, then move to the more aggressive PlastX. I think I can still get the lens covers smoother, so I expect to continue with the PlastX.
A caveat: Remember I was dealing with hard plastic (not something flexible like a convertible rear window), so I was able to use a fair bit of pressure with the PlastX.
Hope this is helpful to others.
I understand the not using pressure part, but what is wrong with building heat? After all, these are headlight covers and they have strong, hot lights behind them. Feel the light after it has been on for a while...it is warm.