This is a 6th gen Nano, manufactured almost a decade ago. It still holds a little charge, but of course not like it used to.

It has not stayed regularly charged (it’s spent several blocks of up to a year with its battery depleted).

I see ebay sellers offering battery replacement service for this model – would that be meaningful? Do these sellers have new (non-OEM) batteries on hand?

Are there other ways I could recondition or refresh such an old battery?