IPod Touch Second Generation Can't, no.. Wont, Charge (the poor thing is trying)

Question

Hello friendly Apple Experts,
I recently had an unfortunate incident when my iPod touch third generation went for a swim. While we waited for it to recover I dug my old iPod touch second generation out of storage (when it was put it into storage it had been completely restored)
Initially it took several hours to even begin charging. It would go from Charging Logo --> Apple Logo (loading screen) --> Black Screen, and start over again. Eventually it was juiced up enough to get to the home screen. After this it reverted to it's normal three hours, or so, of charge time. At first it was running like it did when it was first bought, the battery life was still exceptional. So I synced it to iTunes and loaded it right up.
However, a few days later we dug the other iPod out of the rice and it seemed to be working just fine. So I began to use both, one for travel, the other for at home. Unfortunately the second generation one was put aside for about four weeks and the battery completely drained. Since I had initially rebooted the iPod it had not been completely drained again. At this point, it has been plugged in for several days and goes in a continuous loop of: Charge Logo --> Apple Logo --> Black Screen and then back again. And on yet another sad note, the battery life for the third generation one has been affected very negatively by its little dip.
To be honest I never wanted the third generation one to begin with, the only reason I bought it was because the second generation’s software became completely obsolete.
Anyway, my questions are...
What has happened to my beloved Second Generation iPod touch?
Is there any way to fix it?
and...
Is there anything I can do to prolong the life of the Third Generation device?
Thanks so much,
A friendly Apple consumer.

Answer 1

Not Charge
- See:      
iPod touch: Hardware troubleshooting
- Try another cable. Some 5G iPods were shipped with Lightning cable that were either initially defective or failed after short use.
- Try another charging source
- Inspect the dock connector on the iPod for bent or missing contacts, foreign material, corroded contacts, broken, missing or cracked plastic.
- Make an appointment at the Genius Bar of an Apple store.
Apple Retail Store - Genius Bar                          
Apple will exchange your iPod for a refurbished one with a new battery for $79. They do not fix yours.
Apple - iPod Repair price                       
A third-party place like the following will replace your battery for less. Google for more.
iPhone Repair, Service & Parts: iPod Touch, iPad, MacBook Pro Screens
Replace the battery yourself if you are up to it. Yo can purchase a replaement battery for about $10
  iPod Touch Repair – iFixit