Closing out email accounts

Greetings forum-goers, happy Sunday!

I've been contemplating a question that's perhaps unusual considering that the vast majority of Cox customers wish to retain their email access.

I'd rather close out these accounts and be done with them. Practically zero accounts are linked in any way to these Cox addresses. I personally manage over a dozen different email boxes for myself, and it's overwhelming to maintain.

So what's the easiest way to close out and delete these email accounts in the midst of transition? Would it be enough to never log in to Yahoo!? Would Cox's transition offer expire and delete the emails for good?

Surely there must be an implicit deadline to move off Cox before we lose 'em for sure. I'd just prefer to do this intentionally.

So long, and thanks for all the fish!