A quicker way to get cold is a really cold shower just before bed. It works really well for me, and I believe there are many other benefits to cold showers beyond just getting to sleep.
The cold water grabs the brain's attention. So the brain doesn't let the mind latch onto thoughts... energy contracts rather than scatters
One is to really tense up and to fight the feelings of cold. I don't think this is too beneficial. The other is to really relax and embrace the cold. Taking deep breaths and focusing the mind inwards allows you to accept the cold for what it is. It takes a little practice, but once you are in that zone the shower becomes rejuvenating and relaxing at the same time and really helps shake off the day and get me in the zone for sleep.