some stains just dont come out.....

I have been spending some time with a Jeep Grand Cherokee the last couple of days from a local body shop. The vehicle was extremely dirty prior to the wreck. I mean open the doors and make ya puke nasty inside, mold in the carpets and the once light camel colored cloth seats were litterally dark gray everywhere, Im not exagerating here, the seats were so filthy and stained they were hard and crackly. After 5 rounds with my extractor as hot as it gets (about 200 degrees) and with every chemicle and every stain removal technique i can think o, there are still some spots in the seats that will not come out. So, the vehicle came in because when it was in the accident, all four occupants had Dairy Queen blizzards which ended up in the headliner. I have to wonder who told these people something spilled in their car as it seems unlikely they would have noticed otherwise. Anyway, I assume this car has been filthy like this for at least a year and those stains are very set. I have tried enzymes, spot removers, mildew busters and even solvent, but still when dry the seats look great except for the stains. Anyone have any luck pulling year old nastieness out of this cloth material? The headliner cleaned up great, even the pen marks where some young child was learning to draw dinosaurs!