Occurred to me recently...everyone's experienced a brief spell of lucid dreaming: when you're in a fantastic dream (lying on the tropical beach after winning the lottery) and you realise you're dreaming just as you begin waking up. Such disappointment!

I wonder if rubbing hands or spinning would be able to rescue some of those dying dreams?

Maybe an induction technique could be devised from this - using an alarm clock that starts almost imperceptibly quiet and builds up. Eventually you pick it up out of awareness and know you will wake, but you have time to experience brief lucidity. You could vary the volume of the alarm clock so that you defer your waking times and gradually become adept at lucid dreaming.