This is sort of a show and tell but also I need a little help. I just won 4 yards of this wonderful and super rare fabric on eBay (for a very low price) designed by Andy Warhol and printed around 1955 from a drawing done in 1951 originally intended for a greeting card. It arrived today and there are a few stains on it that I would like to remove. They are black and smudgy, they look a little like pencil. What would be the best way to remove them without damaging the print? Any help would be greatly appreciated. Also would this be something worth donating to a musuem? It's a spectacular print and I've only seen 2 other examples of this print in different colourways.