I have had good luck getting grease stains out of clothing with "krud kutter" (or is it crud cutter? - they spell it funny) I got from Sam's or Lowes, can't remember which. It is supposed to be safe on fabrics. I think it is mostly ammonia. Ammonia is a great grease cutter, so you may want to try some plain old ammonia in an out of the way place and see if it changes the color of the fabric before soaking a big patch on the back of the seat. I just remembered, I did get a big blotch of black grease off of our maroon fabric seats in our old van with the stuff, it worked great.
[This message has been edited by Curculio (edited 10-01-2001).]
[This message has been edited by Curculio (edited 10-01-2001).]