This is a question coming from my mother. She has a doll with an unidentified stain on its ivory-colored satin dress. She describes it as brown and non-oily (possibly Coke or coffee). Without harming the fabric, how can she get the stain out?
Thanks from the mother of Babel Fish 
Take it to a professional cleaners, is my advice.
Apparently the dry cleaners do not want the responsibility of dealing with the doll, and the dress cannot be removed from the doll.
Well, that is a toughie… 
Question: is the doll immersible, that is, can it be gotten wet? What’s the doll made out of? I’m thinking, “First, do no harm”. Soak the whole thing in plain water overnight, to see what happens? Not likely that plain water would hurt satin, but the doll itself is another matter.
Is there a tag on the doll, can you call a manufacturer? Can you call somesort of a doll shop? Maybe even a taylor or (if it’s old) an antiques dealer.