I have a question that is mostly unrelated to tint, but figured the people on this forum would have more experience in this area... I am restoring an older BMW. The rear vent windows(back side glass) are fritted along the edges w/ a black dot matrix and black trim. The black trim right below/outside the dot matrix is faded in a few spots on both rear windows. It isn't super noticeable, but I have the windows off the car currently and would like to touch up the areas where the black has faded away. What product would work best for this? I'm assuming a flat black paint... but is there a particular type that is appropriate for use on glass? Especially fritted glass? Thanks for any info you guys can share!