As far as I know, it is not possible. From what i have read regarding the Joey Mod (darkening the chrome bits within the lights) in order to remove the lens you need to practically bake the whole headlight unit to remove the front clear lens as the glue is rather tough in order to seal it.
I washed my car on saturday and noticed my near side headlight has also begun to get filled with crap, so I was considering a Joey Mod this summer perhaps.