I always take a piece of "safety wire" about a foot long, thread it through the little clippy-doo, bend it to create a hook-like thing, and yank. After the clip is off, the crank just pulls away.
To put it back on, simply put the clip on the crank, align the crank where you want it, and push it onto the splines. It will "click" back into place.
Is someone keeping score, or must I read through the old posts and figure out how many stupid questions I have left?
Do that one and this one count as one or two?