To be perfectly honest, I use dry cleaners for deodorizing - I never hold much hope for actual cleaning. That's because whatever medium the stain was in is what you need to remove it, so water based stains need water to remove the stain. Modern dry cleaning fluid really isn't much of a slvent for anything…
With something like this I start with a brush attachment to my vacuum and see what happens - you would be surprised what might happen. Then I graduate to a damp cloth that is wrung free of nearly all moisture, leaving just enough to remove surface dirt but not enough to actually soak the dress - again you would be surprised what the results are. Then dry cleaning.
