See the little pile of rust on the tray? That would be why the lens is brown. I’m cleaning the fog light up the best I can. But the reality is, a sealed lens doesn’t want to be unsealed making the finger size opening in the back tedious to navigate.
Once the lens is cleaned up, my thought is to line the inside with tinfoil since any ounce of original chrome reflectivity is poof. With the reflective foil in place the light should look pretty good. I’ll do my best to seal it so water doesn’t leave me with another tray of fine brown blow a few years from now.