Stained White Vinyl Seat

[83glxvert]

Finally got the car out over the weekend and my wife's shirt stained the brand new vinyl seat. It has black specks all over it that won't come off. So far I've tried Griots interior cleaner, LA's totally awesome cleaner, and comet with bleach. No success at all with any of those. I've been able to clean these with with the Griots cleaner every other time they've had any marks. Anyone have any ideas or tips? Thanks in advance. Mike