I was told it's a good idea to delete my old email address. I now have a new one. The one I want deleted is a gmail address from around 5 years ago. I've had my new one for about a year.
Go to the account settings of that email you want to delete and there should be a delete account button after searching a little. If you don't have the password for the account then I don't know what to do. By the way you can probably find the solution for this with Google.
A word of warning - any app purchases or downloads will also disappear with the account. If you used that account at all for the Play Store, it might not be a horrible idea to wipe the device and start over without that account. At the very least - go into the Play Store, select the account you're going to delete and see what apps are installed in association with that account.
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