Folex, hands down. You can get it at Target in the home chemicals aisle. I've tried Resolve spotter, spot shot, even TOL's pre-spot, but I keep coming back to Folex. It's not the best for cleaning out ground-in dirt and general filth, but for stains of various sorts, its unbeatable. Using Folex and a little IPA, I was able to get rock-hard pine tar out of a backseat carpet, and get the carpet looking brand new. I doubt i could do that with any other spotter.