I love Oxyclean. A few hours in a hot water and oxyclean solution, and all the beer labels and glue come off of bottles by themselves. There is no scrubbing required. I just rinse the bottles in the sink as I take them out of the Oxyclean and run them through a dishwasher. The wet Oxyclean solution is very slick, like a detergent, or perhaps it actually has some kind of surfactant in it. I'm not sure what's in it, but I do make sure I rinse the bottles very well after they've been in the Oxyclean.
I also use it to clean carboys, my brew keggle, my mash tun, etc, whenever they have grunge that won't come out by other means. For those applications, I just soak for an hour and then dump and rinse very well to make sure I get all of it completely out.