How to fix a black painted grille?

Can you add pics?

It would be easier to suggest methods if I could get a better idea of the paint used and the thickness but without physically seeing it, pics may help. Also, I'm not sureexactly how much has actually been painted. With that being said, the stainless will be the easiest of all to take are of. They will buff out easily. The other areas are a little more sensitive. I would test out a small section of the painted over chrome vacuum plated area just to see if their is chrome underneath or if it was stripped and painted.

Re: stripping. I would highly suggest finding someone who can strip with a dry ice system. They would need the ability to "dust" with it vs the more common larger pellet blasting. These are common n the tech/biotech industries so that may give you a route to locate them. The results are quite impressive and usually saves a lot of prep time and work after the fact.