We introduced a product last year that we developed with Bissel called Quik Out. It comes in both trigger spray and aerosol forms - my wife loves is as we have a small dog at home who, when left alone for too long will sometimes leave a little note for us, if you get my drift. Quik Out works great even on that sort of stain. The problem with cleaning cloth seats though is that spraying too much of anything on them, like, uh, Coke, tends to soak into the padding below so extracting everything can be tricky. I'd use a small amount to start with and a clean terry cloth towel to work it in a bit and absorb as much back out as you can. If you need to do any rinsing at all I'd recommend distilled water as tap water can have a bunch of minerals in that can leave a ring. Always go easy on cleaners and water rinsing when working on cloth interiors.