I redid the tail light housings on a 54 years ago. That made me see right past how bad the parking light husings are on my 55. On the 54 parts, I removed them so they could be really cleaned well. On a super clean surface, I cleaned them with acetone, then masked, and used a new single edged blade to trim the tape. Some rattle can light gray prime, then very lightly spray flat black. Let it dry several hours between coats.