Rebuilding a broken and wet I pod touch

I have two 4th generation I-pod touch's that had cracked face screens and also water emersion (one in salt water one in fresh water). I had no intention of doing anything but throwing them out until I found you web site and susecssfully repaired an i phone 4 with a new battery and rear cover. What are the likeley components that would need to be replaced other than the battery and the front screen?

I would like to see if I can repair these just really for the challege of it.....Im aware replacing them would probably be chepaer...but I want to try.