Let's try a few other things.
Here is another ash tray door that has suffered from time and UV rays.
I masked off the right side, and tried each of these products on the left side.
I really couldn't tell that there was any improvement.
Finally, I tried brake fluid on the right side of the door.
Again, an improvement.
Let's compare the various results.
Actually, the brake fluid was easy, and compared well to the toothpaste method.
The starting fluids were useless; the WD-40 really wasn't as expected. The brake fluid was a surprise.
I guess I could try kerosene or gasoline; however, the WD-40 leaves behind an unpleasant smell.