"Dropped my iPod in water, having some problems"に関する回答dead battery / corroded connection = ipod dies on unplug try opening it up using ifixit's guides. you should check for corrosion on the battery cords. use a toothbrush with rubbing alcohol to clean it off. once thats done, test it. if that didnt fix it, try using a multimeter on the connection. if its lower than the amp-age than the battery advertised, get a new battery. warning: replacing the battery requires soldering, I suggest trying it tho, because this battery is easier to fix than the 2nd gen's.
"Diagnose white screen resulting from water damage?"に関する回答try cleaning the contacts to the lcd screen. if that doesnt work, use a voltage tester to see if the contacts are receiving electricity.