Q: Selling an iPod with music

Legally, you should erase the iPod's music, since the new owner does not own that music.  You should actually erase the iPod touch completely, to remove your personal data.  You can do this by doing a Restore using iTunes.

Use iTunes on your Mac or PC to restore your iPhone, iPad, or iPod to factory settings - Apple Support

Where did the music come from? Do you have proper authorization from the rights holder(s) to sell the music? If not, you can't do that.

You should follow this guide before selling your iPod:

What to do before selling or giving away your iPhone, iPad, or iPod touch - Apple Support

You can't (unless you own the rights to the music)

Why do I suspect that the OP's idea of "old time music" is what was popular when I was in my thirties?

Careful dear, your age may be showing

And I'm darn proud of it, thank you!

Good for you.

if I don't have to ask anyone "who is that?" then it is "old time" music