In preparing to install my new GE Nighthawk bulbs, I tried to clean the
low-beam lamp housings with 90% alcohol.  The left housing now looks
nice, but the right one still has considerable fogging on the reflector
surface.  I made a casual attempt, on areas I could easily reach, to
clean this with alcohol on a Q-tip, and found that it helped.
Perhaps not uncoincidentally, this same lamp housing looks like a
previous owner had split it (glass from reflector) and then reassembled
it using silicon sealant.
So, I'm tempted to break it apart again, clean the full reflector
surface with (gentle) direct contact, and then reseal it.
Someone please talk me out of this!