While the figure functioned perfectly and had no major defects, there were definitely some cosmetic issues. Paint marks were transferred onto the Hulk from other items that he had collided with during rigorous play sessions. From the colors on the toy, I could immediately identify where they came from. Some of the colors came from different painted walls in the house, an old swing-set, a bunk bed, other toys and furniture.
The dark green hair and purple pants however were indeed painted. I cleaned these areas with much less pressure for fear of dulling, or damaging those surfaces.
While the paint thinner worked like a charm, I noticed a bit of a haze and dullness to the figure that wasn't there before. I finally took some plastic polish and applied it to the entire action figure, which in turn rejuvenated and reconditioned the plastic.
I'm happy to say that the figure cleaned up nicely, and looks pretty dang good now. I will eventually give this figure back to my son so he can reminisce about the endless hours he spent playing with The Hulk, but for now, I think I'll leave him on my shelf for awhile to terrorize the other toys in my collection..