[Steve 82SC]

I'm getting ready to fit and install a rubber chin spoiler on my 82. I think it would be prudent to put some sort of a coating on any bare metal resulting from the new holes that I'm going to have to drill in the valence. The leftover POR15 that I thought I had sealed better than an Egyptian tomb is as dry and hard as the desert surrounding the tomb. Other than POR15, has anybody had success with some sort of coating that could be purchased at Pep Boys, Autozone, etc.? Suggestions so far have been Sharkhide metal protectant, Permatex rust neutralizer, and a rubber-based body undercoating.

Thanks,
Steve