Looks like one of my original headlamps is losing its silver lining. I imagine this will affect the luminosity rather severely. Solution is to get a new lamp?

 

If the original silvering (really aluminum spray...) is getting a little dull, a "wash" with windshield washer fluid (NOTHING with ammonia...) and a distilled-water rinse may bring them back. If the metal spray coating is actually gone, replacement is your only option.