Steam cleaning the sofa with a Karcher? Tips?

[minxthemanx]

Fabric sofa, covers not removable. (yep that was a good decision.) Needs a thorough deep clean. I've got a Karcher steam cleaner, but am thinking I need to use some sort of upholstery cleaning liquid with it, not just the steam? Or mild washing detergent? Anyone steam cleaned their sofa with good results?

Following!

As oppose to using your steam cleaner on the upholstery have you thought about using scothgard on your upholstery. I've used it for cleaning my sofa and it does a fantastic job.