I know a couple of pro level opera singers that swear by honey and lemon. Alcohol with a lot of sugar can act as a pretty good solvent to clear mucous from vocal cords, especially for smokers, but it comes at the price of drying out the vocal cords also. If I've had a cold, a lot of times I will use Southern comfort followed by a whole lot of water.
And DJC, what you've heard is true. Many years ago, we were in a hotel where we were staying to see a Janis Joplin concert. In the next room over, a caterwaul of screaming began that was so horrible that we thought some woman was being raped or killed.
We pounded on the door, and it opened up to reveal Janis Joplin, soaking wet, dressed in a towel, with a bottle of SoCo in her hand. She said, "I'm sorry, I'm warming up, am I bothering you?"
We managed to stammer out that indeed, she was not, apologized, and went back to our room. I think she used the steam from a really hot shower to compensate for the drying effect of the alcohol. I have found this works for me also, but I believe one shot is a better choice than most of a fifth. You'll notice she's dead, and I'm not.-Richie