I would get some electronics cleaner or some isopropyl alcohol (>90%) and a soft paintbrush.
use the [guide|423|logicboard guide] to disassemble the iPod.
clean everything "odd" looking (white/greenish residue) with the IPA and the paintbrush.don't forget the dock connector. let it dry - reassemble it and try to power it on.
if it wont power on, try to charge it - it could be that the battery got discharged while the whole whashing/cleaning process