Can't remove SHIMANO Nexus FC-C6000 Crankset I'm stuck trying to remove my SHIMANO Nexus FC-C6000 Crank from the SHIMANO BB-UN55 bottom bracket. I've removed the bolts fine but can't get the cranks apart. Any suggestions?
You need a crank puller.  It threads in to the crank arm, and presses on the bottom bracket spindle to pull the arms off. 



http://www.parktool.com/product/crank-puller-for-square-taper-cranks-ccp-22

A video here from Park Tool on using their crank puller: