Other than the lens getting dirty on the inside and dust coating the silver reflector surfaces, probably not a lot that can be done.
BUT, wash everything down first. Reflector bodies, inside of the lenses, etc. Find a filter cigarette filter and put it in the small indentation of the reflector housing. Might use a thicker gauze section from a band-aid, too?
After the reflector is cleaned, the find some bright silver paint to repaint it with. Possibly Eastwood has such a product, but local WalMart (or similar) might have some Krylon or similar. Even some of the "spray chrome" paint?
In many cases, over the years of magazine articles, just cleaning things up (reflector and inside of the lens can make a significant difference. Putting the "silver" back on the reflector (which was not really a shiny silver anyway, OEM) makes it better still.
As for gasket material, probably a thinner bead of quality silicone, of the correct height, can work. Just let it cure a few days prior to installation. Might be some sealing foam that might work, from Home Depot or similar? Provided it's of the correct weather tightness and dimensions.
Polish and wax the exterior of the lens for maximum light transmission and clarity.
Enjoy!
CBODY67
