I used to own one of these before upgrading to the Rocky. I too could not work out how to pull the burrs apart. From memory there is a central nut that one can undo, but I did not have a spanner that could get in tight enough.
I did find that the plastic grill where the coffee exits the grind chamber a pain! (MAJOR reason of upgrade) The horizontal exit route was always inexplicable and illogical to me also. Coffee would always get stuck in the passage, particularly if one was using relatively oily beans. What I found was that using a chopstick I could mostly clear this passage. This I found to be the most important maintainence on the MC2002. Remember to unplug the grinder before sticking the chopstick into it!!!