Mine is brown (Bought it on the car that way) Can I treat the grille with chemicals, CLR, or something to bring it back? I might scrap it but it's very straight and solid, just brown, like there was an engine fire in the past or something, who knows. Thanks for any info. I assume it is aluminum, just don't know what I can do to bring a more silvery and shiny finish out.

Yes, I believe it is aluminum.

Try a cleaner for cast aluminum wheels, the caustic kind that etches the aluminum. It sounds like you have nothing to lose.