A quick web search yielded predictable advice such as "power off the machine and use a paperclip to extract the disc" or "disassemble the machine and DVD drive to remove the disk". Since I wasn't keen on scratching the optical mechanism to ruin or dismantling the computer, I kept scrolling until I found the following blatantly obvious and blatantly sensible suggestion from 'ashleyman':
"Or just tip it so the drive faces the floor and give it a few taps!!"
This served me well and I safely removed the CD within 5-10 seconds of gently shaking and tapping the laptop with the slot facing down. Sometimes the solution is so obvious that you can completely pass it by!