A few weeks ago I restored the headlights on my 1963 Volkswagen Beetle, they were all rusted inside and looked really bad. I had been looking into buying new replacements but decided to go ahead and restore the original Hella headlight assemblies that I have on this bug. These original German-made headlight assemblies are of much better quality than the replacements that come from China, Brazil, or wherever else they come from.
First, after removing them from the car of course, I took pictures of the assemblies to make sure I knew how to put them back together the same way. I then disassembled them completely, cleaned every piece (even the clips) with rust remover and a steel wool, used fine sand paper on the pieces that still had some rust, and painted the interior metal housings with a flat grey rust sealer paint. The glass covers and light bulbs got cleaned with some glass cleaner, and I also took the time to clean all the electrical contacts with a little bit of sanding with fine sand paper.
After waiting a couple of hours for the paint to dry I went ahead and put these nice VW Hella headlight assemblies back together. I wish I had waited longer for the paint to dry because some of the parts where the metal touched metal the paint chipped away a little. So I recommend to wait at least a day or two after painting to put them back together.
The job was not hard at all. I was a little hesitant to disassemble the headlight assemblies at first after seeing all the pieces they contain, but putting them back together was pretty easy and straight forward. Just make sure you take some pictures before taking them apart, or at least do one at a time so you have an assembled one to look at for reference.
One thing I do want to note is that all the original Hella stampings faded away when cleaning the surfaces, which I was pretty bummed out about. Oh well... at least I know they are original. Also, the outer chrome rings where so pitted that I will have to replace them to get the whole thing looking like new. Also, I did not get a replacement rubber seal that goes between the glass cover and the metal housing, instead I used some black adhesive sealant which I think was good enough.
I spent about $20-$30 in materials and a whole day doing this headlight restoration job. I think it was well worth it, both for the experienced gained and the satisfaction of keeping it original and doing it myself.