Stoner Carpet Cleaner dude...that's all you need to know. Order it online if you can't find it in a store. I've never seen anything that works anywhere as close as the Stoner stuff.
Not chit guys, I've seen it take a coffee stain out of carpet that was there for 2 years! A buddy of mine use to drive his aunt's Buick that had blue carpet and she'd spilled coffee in the floor. For chits and giggles I wanted to see how good the stuff was and it worked! It's got a crazy strong smell, but if you clean your truck just leave the windows down for a few hours and it's not bad.