Yesterday I helped a Mac mini owner who had a CD stuck in the optical drive. It wasn't a physical jam. The mini simply didn't recognize the CD and therefore didn't offer any way to eject it. The Finder didn't see it. Disk Utility didn't see it. And holding the mouse button down while booting didn't eject it. The solution turned out to be as follows: Switch from a wireless keyboard to a wired keyboard. Shut down. Hold the D key while booting to launch the Apple Hardware Test. Choose Shut Down. The disc ejects. I hope this tip will help others in the same situation.