So with my E34 having 190K miles on it now (:(), I've noticed that the headlight lenses have collected a lot of grit from normal driving conditions. The grit can be felt very obvious if you run your fingers across the lens. Is there any way to clean or buff the lenses to a smooth, clean surface again without having to replace them?

+1 for this question! I've got that same problem too :(

I can't really think if wet sanding them with some high-grit sandpaper would help or just dull them up...

3M makes a Plastic Cleaner that is a very light polishing compound. It works wonders on plastic instrument clusters and turn signal lenses. Not sure what it would do for a glass lens.

bavauto.com actually has clear plastic (vinyl...? anyone know these as well?) adhesive covers that you peel and stick to the lenses. i have them, and as of yet, no yellowing or dings. that may help.

I replaced one of my broken headlights with another used set and the used set is not as clean as my original set so I did some research to try to restore the headlights to match. I found that there is some stuff called super cerium oxide. I purchased it off ebay for pretty cheap and when mixed with water and polished onto glass, its supposed to restore its original look.

It kinda looks like cocaine but its used to polish rocks and glass. Its supposed to be the best way to clean glass.

I havnt tried it yet but I will post some pictures after I do. Dont know when ill get around to it tho.

One of the painters at my shop takes the plastic-lensed headlight assemblies out, wet sands them with a very fine sandpaper, then shoots them with clear-coat. They look like new when he's done. Also I hear that there is a company that goes to the various used car dealers lots around town and makes all the plastic-coated headlight lenses look like new, for a fee. Not sure what process they use but the car never moves so I'm sure there is no painting involved.

I replaced one of my broken headlights with another used set and the used set is not as clean as my original set so I did some research to try to restore the headlights to match. I found that there is some stuff called super cerium oxide. I purchased it off ebay for pretty cheap and when mixed with water and polished onto glass, its supposed to restore its original look.

It kinda looks like cocaine but its used to polish rocks and glass. Its supposed to be the best way to clean glass.

I havnt tried it yet but I will post some pictures after I do. Dont know when ill get around to it tho.

Thanks for the heads up on that product. I'll look around and see if I can dig some more info up regarding the results. Don't forget to let us know how yours come out! If that method does work, I would be hitting two birds with one stone. I fudged up my windshield with some acetone and I'm hoping it would fix that, too.

One of the painters at my shop takes the plastic-lensed headlight assemblies out, wet sands them with a very fine sandpaper, then shoots them with clear-coat. They look like new when he's done. Also I hear that there is a company that goes to the various used car dealers lots around town and makes all the plastic-coated headlight lenses look like new, for a fee. Not sure what process they use but the car never moves so I'm sure there is no painting involved.

That would be great... if my headlight lenses weren't glass :stickoutt. I've wet-sanded plastic headlight covers before and know how that method can turn them completely around. But for glass, I've never tried it. I would only imagine that it would cause a visible haze since the surface is much, much smoother than any plastic.

Cerium oxide works. You need to wetsand first with 2000 grit and then use the serium oxide with a little water and buff with a leather or felt pad. I have the real nice projector hella fogs. I need to get the polishing kit for them as they lens a re pretty beat up

Why leather or felt pad? Couldn't you use a some sort of wipe? like a link free wipe or microfiber?

From all the research I have done... Leather pad is the absolute best. Leather pad on a buffing tool at around 1500RPM. Felt pad is second best.

Microfiber will not buff out scratches

Thanks for the suggestions, guys. I've bought 4 oz. of the cerioum oxide powder/chunks via eBay and I'll let you all know how the results come out when I complete the cleaning. RVAE34, I'll be sure to try out a leather pad if I can obtain one. If not, I'll try felt.

So a little update:

I tried this stuff and I've gotten nowhere after an hour of buffing. I had some old glass jars sitting around that were scuffed/scratched and practiced on them with no avail. I think I just wasted $8 :stickoutt

Oh well. I suppose I'll just buy some new lenses.

I'm sorry to hear that. Maybe your scratches are too deep to repair with the powder. There has got to be another solution.

You sure you're not actually seeing the dirt/dust collected on the INSIDE of the lenses?

You sure you're not actually seeing the dirt/dust collected on the INSIDE of the lenses?

I actually peeled one of the lenses off (on accident) and found that the inside of the glass was 100% clean and "smooth as glass"... to use an ironic metaphor.

I've done a little reading and found that they could be sanded with 1500 or 2000 grit paper, depending on the severity of the blemishes, to rid of those blemishes. Only AFTER they are sanded should they be polished with Cerium Oxide.

Meh - I'll just buy some new lenses if it's going to be that much trouble :dunno.

I think BMP has replacement lenses for something like 39/pair.

bavauto.com actually has clear plastic (vinyl...? anyone know these as well?) adhesive covers that you peel and stick to the lenses. i have them, and as of yet, no yellowing or dings. that may help.

I bought that sheet. It has fogs and four headlamp outlines scored thru . I used the ones for the Fogs when I bought a brand new pair and they went on fine, I cut them carefully and they aren't readily visible and they still look new. I can't see using them on already sandblasted glass though so I'm waiting to use the headlamp sets for when I buy new lamps but I highly recommend it just be sure to follow the instructions to the letter.

I need to look into this some more now. My headlights are all 'pitted' up and I have tried just about everything to 60 (?) grit sand paper and can not seem to get them out...

You can buy a new set of acrylic lenses for e34's. However, they can melt with upgraded HID bulbs installed.

You can buy a new set of acrylic lenses for e34's. However, they can melt with upgraded HID bulbs installed.

Um, no they can't. HIDs burn a lot cooler than Halogens.

Um, no they can't. HIDs burn a lot cooler than Halogens.

Plus, there is a VERY thick layer of glass (the convex orb) between the bulbs and the outside lens.

umm, why not get all the GRIT out of the lens and shootthem with clear SEM chipguard. It'll fill the pits and make them look like new according to the older members at b.i. aka bimmernut.com

I decided to just buy new lowbeam lens assemblies for my E-codes from the dealer, wasn't a terrible rape-age. might have posted a price in my 'smoking a lot of things' thread

Um, no they can't. HIDs burn a lot cooler than Halogens.

BMWlight.com has acrylic lenses for sale. I wanted to buy a set but I planned on getting HID's. I emailed their technical department and their tech told me they have had burning and discolorization issues with acrylic lenses with HID bulbs.

So the manufacturer of acrylic lenses says do not use with HID bulbs.

Plus, there is a VERY thick layer of glass (the convex orb) between the bulbs and the outside lens.

Wouldn't the convex bulb help to intensify the light beam, generating more heat?

umm, why not get all the GRIT out of the lens and shootthem with clear SEM chipguard. It'll fill the pits and make them look like new according to the older members at b.i. aka bimmernut.com

I decided to just buy new lowbeam lens assemblies for my E-codes from the dealer, wasn't a terrible rape-age. might have posted a price in my 'smoking a lot of things' thread
Orly!?

Seriously, how well would you say (or have your heard) about the filling ability of SEM Chip Guard? The headlights I have are very pitted up. I'd take pictures if I could.

run a search on bimmernut for SEM chipguard and judge for yourself... having not used it (nor ever had severely pitted lenses) I can not do more than speculate.