Sheesh - reading this thread is giving me a bad hangover. (Says the guy who used to buy a liter of Bowman's Virginia Vodka for less than $5 in college, and who therefore is VERY familiar with hangovers caused by cheap booze.)
I use Bowman's Virginia Vodka in my airlock when I'm cold crashing. Starsan otherwise. Or tap water if the fermentation is banging away.