i use 409 ... spray the whole seat not just sections or else your gona get one REALLY clean spot and it's going to look bad. after you spray the seat scrub a little and try to clean out what you can with a moist rag.
i work for a car dealership, and we use soapy water and a big shop vac. I have never had a stain i couldn't get out. That could be a good slogan for something.