This may be a weird question, but here goes. Is there a way to clean a glossy dust jacket that has these spots. I'm not sure what the spots are from, perhaps dirt or somesuch. I'm sure you guys will know what I'm talking about. I just bought a book that has a dark dust jacket and its beauty is ruined by these rather numerous spots all over. Rubbing it with a napkin and my shirt did not produce much of a result. What to do?