de fishing soap out of California, google it or click the link, smells kinda like liqourish and works well http://defishingsoap.com/
Guy I work with keeps one of those aluminum bars with him all the time. I don't think it does anything miraculous...he's a strange dude anyway, so I don't put much stock in his odd ways.
Apple cider vinegar will take away the fish smell, crab smell and clean your cooler.
I have to admit, I've learned a lot lore from this thread than I thought I would have.