Tip - How Do I Remove Water Stains from a Poster Print? — Good Questions

Q: Maybe someone can help me with this tragedy? This is my beloved Superflat exhibit print poster. Eight years ago I got it mounted, but when I moved to NY I didn't ship it out and stored it in my parents' basement. Now I've moved back and discovered they had a flood one year and this poor print got some water damage. Is there any way I can remove the stains without damaging the print? I was thinking of a Mr. Clean Magic Eraser just on the white areas of the print, but I'm scared....