As an ardent DIY-er, I've been called a miser and a perfectionist, and quite frankly - I agree. I am a miser and and I am a perfectionist - when it comes to my car nothing but the best... at a reasonable budget.
So when my badly weathered headlamps started to look like all milky and yellow, I thought about cleaning the haze without blowing 6 holes in my pocket, I know Bee shared his method of solving this issue and quite frankly it's pretty do-able. But something about sandpaper scares me. Accidental damage with sandpaper is irreversable regardless of how easy it is to fix.
So I asked around and consulted Google, and ended up with 3 supposedly effective removal methods.
1. Toothpaste! Yes, this nifty flouride packed toothwash apparently is a capable contender in this showdown. Sworn and proven by the 'older' generation of car fanatics - specifically my fathers generation.
2. Autosol! Several DIY enthusiasts swear by this miracle cream but I'm reserving comment and will let the results speak for itself.
3. A plastic / headlamp cleaner! In this case the tool is Meguiar's Plastx which I quote : "This easy-to-use, rich gel formula quickly restores optical clarity to both rigid and flexible clear plastics. Cutting-edge advancements in Meguiar’s® exclusive Microscopic Diminishing Abrasive™ Technology (MDAT) remove light oxidation, chemical degradation, surface contamination, stains and light surface scratches with ease".
I am by no means a good detailer. So to do this test it's only appropriate that a professional detailer carries out the tests, so I enlisted an old friend of mine - Kenneth of Wetshine.net fame to do the dirty work. We spent a good 30 minutes discussing the headlamps, microscopic marring, cracks, camera zooming, halogens, etc before we actually got started on the test.
First up, 1 of the affected headlamps was divided into 3 sections to showcase the differences between the 3 products. Initial cleaning of the headlamp was done using the usual car-soap and water and no claying was done. The first headlight was treated using only a microfiber sponge and water, not with a rotary buffer.
Wax on.... wax off (toothpaste on... toothpaste off). A quick rinse with water and a wipe down with a dry cloth to see the results.
And wow... on the left is the toothpaste section and the right is the untouched section.
The toothpaste did a pretty impressive job of removing the oxidised yellowish tinge! But upon closer inspection, it did nothing to 'cut' the top layer and the surface was quite bumpy to touch. Meaning dirt and what not was still embedded there but with a toothy minty smell!
Not bad for RM4.50! (USD1.00)
Next up - Autosol! The same process was applied with the same amount of pressure. Wipe on, wipe off, rinse off and dry off. Autosol however took more time to buff off compared to the toothpaste.
Gah. It was badly scratched all over! Upon closer inspection the dirt and what not had been removed and the surface felt smooth to touch. Clean but scratched... badly!
The same application method was applied with the PlastX product.
The amount of effort it took to apply and remove PlastX was similar to Autosol. Perhaps it's because toothpaste is water soluble so it was easy to remove.
This product produced the best results! Yellowish oxidation was removed, minimal scratching, smooth to touch (dirt free I presume) and had this really nice cherry smell to it.
Final result. You can already tell that the PlastX (right-side test spot) yielded the best results for manual hand application. The worst was Autosol (middle test spot) and since it's a metal polish, the abrasiveness was expected! Toothpaste (left-side test spot) was surprisingly effective though.
However I have to point out that the test that lasted the longest was PlastX. Toothpaste oxidised quite quickly after that (about a month) followed shortly by Autosol. (This test was done separately and is not shown here).
Next test - machine polishing (specifically with a rotary buffer) with the exact same 3 contenders. As always, the ever diligent detailing guru taped up 3 sections on my other worn out headlamp and the surrounding metal parts so as to not accidentally rub on the painted surfaces.
Again, first up is toothpaste.
Again the results were amazing! Toothpaste does pretty well with the rotary buffer. It was obvious that the toothpaste did nothing more than just remove the oxidation layer - it still felt uneven and had 'hills and mountains' and wasn't smooth at all to touch. Not that it really matters but later tests showed that toothpaste again didn't last very long. Perhaps a wax coating will prolong the cleanliness of the toothpaste cleaning.
Next up Autosol.
Same technique, rotary on, hand buff off.
It was clean, smooth to touch but it had visible swirls/scratches which resulted in a not-very-clear finish.
Lastly - PlastX with the rotary.
As expected the PlastX produced the best results. Smooth to touch, no uneven surfaces, very little to almost no scratching, clean and it was the longest lasting among the 3 before it started to oxidise as well (about 6 months).
Final comparison was a professional cleanup. A combination of Osren, Meguiars, GTechniq and a rotary buffer for the final comparison.
Needless to say this yielded the longest lasting results and clarity (until today a year later) and was flawless in terms of clarity, embedded dirt, etc.
The loser here is Autosol. But hey, it's a metal polish, what did you expect - a miracle?
PlastX was the best. But at almost RM70 (USD16+) a bottle, it's not exactly cost effective. Buying it the first time is always the hardest, but once you get past that you're somewhat forced into using it and making sure it doesn't go to waste. So if you can look past the high initial cost and have multiple cars to keep polishing, then this probably is the product for you.
However toothpaste is my choice since it's cheap and I'm a miser. I can even share it to brush my own teeth too to maintain this nice toothy smile of mine.
But I'm a lazy ass. So I'd rather pay a professional to do it for me.
Nothing beats a professional job. But you can get pretty decents results with the proper cleaning tools and toothpaste, as long as you're into cleaning the headlights quarterly!