When I first saw the Skydeck at the dealer I asked about removing the stains on the wall fabric, the dealer said he used a product that NASA uses in SPACE and he got no where in removing the stains.
I was not sure what caused the stains either, but I have since found its water getting in the extruded top rounded corner piece where the ceiling meets the walls. Somewhere water is getting in and filling this 40 foot piece of metal, and then the ceiling trim is screwed into this and the water leaks around the screw and gets the fabric stained with rust.
I had tried a wet vac and decided I cannot fix this, and would start looking for replacement fabric. I have NOT found new fabric of this pattern but I did find a product called
InstaGone. Decided to give it a try. I was surprised with the results, not perfect but may allow me to keep my wall fabric:
I know OxiClean has been recommended and I will probably use that to try to scrub the walls as they are not uniformly white now.
-Randy