I had previously popped open 4th & 5th generation iPods for maintenance & upgrades several times, with no problems.

I couldn’t get this one apart, so I turned to a local cell phone repair shop, who popped it open in just a few minutes while I waited (thank you, Cell Phone Repair of Tustin!).

Once apart, this guide was very useful for the remaining steps.

Battery replaced with iFixit’s battery (and case cleaned up & outer surfaces polished ). Battery life is fantastic now—thanks!