Some interesting tidbits... Thanks!!
Like Toyguru said, most of the details on many many toys are hand-painted.
Creating and setting up an mechanical assembly line to automatically paint such intricate details on stuff that isn't produced in the millions of units would cost a fortune! :)
But obviously there's some kind of process involved other than just some guys/gals in some building with a paintbrush and some paint, right?
Take an eye, for example. On He-Man, there's white, blue, black, and brown. The brown borders the white, which has a thin black layer surrounding the blue, which has black within it and a white speck somewhere, too. Now how does someone painting by hand pull that off?
Like scott metzger said, it has more to do with masks, which block off areas while exposing others for paint.
They just plop them over the area they fit, and paint away or airbrush it on.
The 4H could explain the process really well.
There are probably customizers here who are also familiar with how it works.