'68 B'cuda inner (plastic) grill detailing tips?

To chime in here is the plastic "rechroming' that most places do is a vacuum metalizing process, it will not last long on an exterior. That process is used for interior plastic parts like gage bezels, and armrest bases, and in those applications it still doesnt hold up well. Just a spritz of windex will spot it and ruin it.
I had PARTSMONSTA do my grills. I had done a lot to them and painted the inner plastic flat black, I thot the might have come that way from the looks of them. When I got them back from him, he had cleaned and repainted the appropriate colors on them, including the chrome look on the leading edges. I have no clue how he did it. You might try to contact him----------