Thank you for your reply! To answer your questions:

-The battery was from an older N900 that died on me a couple months before (it got washed in the washing machine . . . I have terrible luck with these phones).

-Both batteries involved, I would put in the water-logged phone and it would light up the backlight (which is all it ever does, since it's dead-dead). So that tells me they both have some juice.

-I had it sit plugged in overnight, and am very patient about trying things maybe 5-10 minutes apart from each other.

-The chargers I use both are Samsung but use the same connector. The only thing I'm wondering about (though I imagine it doesn't matter) is that they are wall chargers, but with the option to remove the USB... Something exactly like this: http://goo.gl/cnvOO I also tried via USB to my computer, but got nothing.