Richard,
You need to get Tamiya Acrylic paints # X-44 Blue and PC-1 white and gently mix together untill you get the perfect colour.
Try a bit and if your not happy just wash it off with water.
Remember after youve touched it up put a little mylar over it to protect it.
Youve seen first hand a job i did on my AFM.
Now you know who i am