Whats a good stain remover?

http://smg.photobucket.com/albums/v626/tmc2k1/?action=view&current=back.jpghttp://img.photobucket.com/albums/v626/tmc2k1/back.jpg

You cant see it much cause i took the pic with the little lift down. You can see above the lift the brownish darkish stuff on the carpet(inbetween back of backseats and top of the lift. Whats a good stain remover to get this out? Ive tried a few things and it worked a little bit but not completely. Thanks!

cant just replace it?, because i dont think you will ever be able to get that stain out completely but if you must try i recomend oxyclean it really does a good job.

sorry another idea just came to me ... what about dying it?

May sound weird.. but I actually found Armorall to be good at stain removing. It really helped clean alot of the stains out of my own car. I'm still confused on how or why it cleaned stains. But it did a really awesome job. You could try that, or as Bandit said, Oxyclean works pretty good too. I'm sure any standard carpet cleaner will work pretty good.