Any way to get stains out of woodwork?

I have a green stain in my woodwork on the floor from one of my son's projects from school, I believe it was paint or something along those lines, not quite sure but I can't get it out. I tried Old English, Murphy's Oil, sponge, even brillo pad (lightly). Anyone know what else I can do? Also, the floor is pretty run down (7 years old) and I was wondering if there may be anything to bring shine without ruining it more?