Doing winter **** bike detailing and stepped back to admire newly installed piaa headlight bulb and noticed how crappy the inside of the reflector bucket looked. With 12K miles on and one burned out bulb the inside looked like a thin layer of skim milk on it. removed and opened it up, wiped out with wooden dowel and microfiber towel, looks like new. Just a heads up for every last candlepower.

 

Ya, the piaa bulbs have a coating, best to fire the bulb hanging by the wire before you put it in the light and let it burn off, that's what makes the reflector cloudy. Denatured alcholhol works to clean it also.

 

Much has been written about this. The other option is a bit of dish washing soap and water sloshed around inside the reflector and lens assembly. The milky coating is especially common inside the passing lights. I have done both the wiping of the inside of the lens and reflector and the sloshing with soap and water. I have had better and more long lasting results with the soap and water. Dry with compressed air or a hair dryer.