Although the Volvo is rarely on the road, much less on the road at night, I thought it'd be wise to improve the anemic tail lights. I'd considered installing some LED bulbs, but after reading more about the pros and cons of LED conversion (unidirectional, current matching issues), I decided instead to improve the stock incandescent setup.
Upon removing the tail light lenses, it was immediately evident that a large part of the problem was simply corrosion rendering the reflector basically useless.
before cleaning. gross.
I started by cleaning off as much oxidation and rust as possible with a wire wheel, and then steel wool. I also used a battery terminal brush to clean out oxidation from the bulb sockets, and gave all the contacts a light sanding.
mostly cleaned and looking much better.
I was originally planning on wet sanding and polishing the reflector to a mirror finish from there, but realized a few minutes into polishing that rust would very quickly render my efforts futile. So I changed courses and "resurfaced" the reflector with aluminum duct tape. After sticking and trimming the tape, I burnished it down with a soft plastic spatula, and then polished it with polishing compound, leaving a pretty satisfactorily reflective finish.
not the Hubble Telescope, but it's acceptably shiny.
Next, I cleaned the lenses (which had been caked with grime) with Simple Green and a soft toothbrush, then used polishing compound to bring it up to a shine.
I was actually somewhat surprised by the efficacy of this approach. I'd say that perceived brightness was improved by about 50%.
dirty on left, cleaned and polished on right