Dude, are the marks due to "gum adhesive" or paint discoloration? Kung gum adhesive, baby oil and similar liquids would do. Kung paint discoloration, sa tingin ko rubbing compound would blend the light and dark areas (siyempre, medyo tatangalin ng kaunti yung light areas). Of course, the best recourse would be a refinish, but that would take away the mojo.