I scrubbing-bubbled the tub and shower, scoured out the toilet with the teflon-laced blue goo, and wiped down all the counters and mirrors. One of the sinks was draining slowly, so I pulled out the stopper thing and cleaned all the soap scum off of it, but even with the stopper completely out it wasn’t draining well. So I got the plunger. Anyone who is smarter than me or has tried this before can start laughing now.
I lined the plunger up with the drain in the slowly-swirling water, steadied myself, and plunged one short and powerful plunge. One, because that’s all it took to get a jet of nasty black soap-scummy water shooting out of the overflow valve, covering the counter, the mirror, and parts of myself with icky, slimy, gunk. I am very glad there was nobody around to see the look on my face when it happened.
Good news: the sink is draining fine now.