Leak Stains

Try a little rug/upholstery cleaner on a damp sponge. Squeeze a few times to get some lather, and then rub it on gently on the stained area. Keep at it for a while and add more cleaner as needed. Results may be better after it dries. (Caution - read the container which usually suggests you try it on a hidden area first, if you can, to make sure it doesn't remove color.)

I used rug cleaner to get some water staining off my cab area ceiling after the plastic cover of the vent van developed a hairline crack, causing a leak that drove us crazy until we figured out the source.