Happy days ! I've used AutoGlym Interior Shampoo and it's brought all of the marks off. I've been using AutoGlym Shampoo for years when I had my Teg and STI on the seats and it always brought them up like new. As it is also for vinyl I thought I'd give it a go. The cloth was black with the Simoniz stuff. So don't use Simoniz cockpit shine on your S. Should have used AutoGlym in the first place !