There is foam under the cloth.  Some solvent cleaners are just fine for the
cloth but not so good for the foam.  If you can, take off the seat covers
and clean them exclusive of the foam bolsters and so on.  SewFine makes some
fine covers should yours be beyond salvage.

I wonder how many of us have actually been saved by child seats, or tiger
repellant.  None in my immediate circle of friends or friends children but
then I live in California, the granola state (mostly nuts and flakes with a
few dried up fruits thrown in).  Clearly your mileage and cost per mile will
be different. Fotos of the recent desert wanderings can be found at
http://picasaweb.google.com/anasasi/TourDesFleurs2008.