I recently got a Batman Forever and for some reason the paint was badly faded on the speaker grilles. I decided to touch them up and documented here in case anyone is interested. The black paint on the speaker grilles was faded on the left and almost completely gone on the right. Oddly, the bright green question mark in the middle of each speaker was intact. I wanted to repaint the background while not touching the question marks.
I started by taking off the front panel and determining if I could take the speakers off and get to the grille. Unfortunately the front plastic was glued on in places and I really didn't want to break it. I decided to remove the front panel and work on it in one piece. I taped some "feet" onto the back of the panel so that the panel wouldn't be resting on the electronics.
I used some frisket film to mask off the area around the speaker and the speaker grille itself. I then used an exacto blade to cut around each question mark. I removed the frisket on the black part of the speaker grille and taped off the rest of the panel. I then spray painted from a distance, only barely misting the area to avoid any pooling or dripping paint. Once I had a good coating, I let it dry and then peeled off the green sections. I think it turned out pretty good and is much better than it was before. It has really been bugging me for awhile so I'm glad it's fixed now.