If the wall is covered with a kind of fabric.
I have had great luck with Folex,on my ceilings just spray it on and BLOT don't rub,you will be amazed at how it lifts out the stains.
It may take more than one application but it took out all of my stains.
You can get it at most big box home improvement stores or
Amazon check out the reviews and pictures.
2006 TIOGA 26Q CHEVY 6.0 WORKHORSE VORTECFormer El Monte RV RentalRetired Teamster Local 692Buying A Rental Class C