toulene
hardware stores no longer carry it, at least not in California, but you can find it at industrial paint supply outlets. pay close attention to the cautions on the label, it's nasty stuff, but it's what's used for thinner in industrial-type contact cement, which is most probably the glue you're trying to remove. don't get it anywhere near the seams on your dink. works miracles on dirty fenders, by the way.