A glass containing the remains of last night's now-cloudy bourbon prompted me to review some old threads on the topic of cloudy bourbon. Along the way I also searched for posts regarding proper methods to clean bourbon glasses.
I found this highly relevant link in an unlikely place.
Now perhaps Professor Ed's illuminating post on this subject will be easier for someone else to find in the future. (I keep distilled water around anyway to recharge the small humidifiers I keep in my guitar cases. I'll at least try Ed's test for surfactant residue.)