interior wall cleaning or replacing

[Hardenburgh]

I have recently purchased a 1994 excella. I am cleaning on the inside and just had a carpet cleaning company come and clean the interior walls in the front and rear bedroom. they were pretty dirty but there are alot still stains. Does anyone have any secret on how to clean this white fabric? Or am I looking at replacing it if it will not come clean enough to please my wife? Is It replaceable with some other material?

Thanks for your help.