I looked back six pages in the Coffee Break folder so I could resurrect this thread and tell on myself.
So, okay, this evening I had an... incident with the toilet, and I had to get out the plunger--serious-looking black rubber thing on a wooden handle. Not just the simple rubber suction cup, this is one my dad got me with extra... shape. Anyway, so I dealt with the toilet successfully and then I was trying to clean the plunger, because... ew.
After trying without much success to rinse the inside of the plunger without touching it or indeed even looking at it, I decided to let it soak in the bathroom sink for a while, so I plugged the drain of the sink, filled it with water, and let the plunger soak there. Now, my bathroom sink and I have also had our differences. I've been liberal with the Draino and I finally got it draining slightly faster than molasses and thought I would just have to live with that.
So I let the toilet plunger soak for a while, then I unplugged the sink drain to let the water out. Then I decided to do a little plunging in the sink with the plunger, in the hopes that this would get fresh water inside the plunger in the same places nasty water goes, to help rinse it out. So I plunged a little, over the drain of the sink because there wasn't really any place else, and all of a sudden there was this roaring noise, and then the water just... shot straight down the sink drain, emptying the entire sink in seconds.
I swear to you, I had no idea you could use a toilet plunger to clear a clogged sink drain. I'm going to try it on the bathtub drain next.