Force eject a stuck DVD

What to do when a DVD is stuck in the drive on an old iMac, and it refuses to booth up? There are numerous ways of doing this, including:

• Start up while holding down the mouse button.
• Start up while holding down the Option key, then hit the eject button.
• Start up while holding down Command-Option-O-F, to enter the Open Firmware prompt, then type “eject cd”.
• Start up while holding down Command-S to enter recovery mode.

Unfortunately, none of these worked. Finally, I found a tip about just physically stopping the DVD from spinning up during boot. So I tried sliding a few yellow note-it stickers inside of the DVD drive. This nicely prevented the drive from spinning up, so that the regular boot procedure could continue. Sometimes a mechanical solution is the best.