After using many different over the counter cleaners and such in auto stores and the like,i've found renting one of those upholstery cleaners you see at common grocery and other stores for 10-20.00 a day to be the most effective and easiest.NEVER use a hard bristle scrub brush on the seats,weather it be vinyl,leather or fabric,it will scratch leather and vinyl and will also loosen the fabric up and make it look like crap.
I always rent the machine and use a very soft scrub brush with a spray can type upholstery cleaner first,if you have any stains this will loosen it up,then use the machine to go over it all as you are instructed to do so,this cleans and removes any dirt or residue completely.
If you just use the spray can type they have,it just scrubs it and then you have to vaccuum as much as you can get out,but it never gets all of it,the machine will thoroughly remove it all without damage.
As for leather and vinyl,clean thorougly with a leather/vinyl cleaner,but do not soak it,it'll leave water stains,then let dry thoroughly and use a leather/vinyl protectant....regular armor all and the like is a no no for that,unless it says specificaly for leather or vinyl upholstery,it will leave stains and dis-coloration and will eventualy damage it..ask me how i know.......lol
As for carpet,like was already said..the best way is to remove it and scrub away and let hang dry.
Don't DREAM your life, LIVE your dreams
Never forget 9/11
"Welding is like a woman,Get 'er HOT and Penetrate"
Gotta LOVE a person who knows everything about NOTHING
The only Thing necessary for the Evil to win is a good man to do nothing....
"How far you go in life depends on your being tender with the young,compassionate with the aged,sympathetic with the striving,and tolerant with the weak and strong--because someday YOU will have been all of these"....George Washington Carver
Want to know what an Ironworker is and the job scope of a Journeyman?..click here...http://www.ironworkers.org/becoming/careers.aspx