I think it was BJ who posted some excellent results using a powerwasher hooked up to hot water for removing winter-cut bark and cambium. I tried it my self once using just cold water and it worked incredibly well.
Otherwise, my best results came from a method that PatM suggested, which was to get the bark off without violating the cambium, then use a spoon to work it off as best you can. Hickory has small ridges on the outer surface of the wood that are difficult not to knick.