Where is Auto-complete for email address?

I use Gmail in Win 10. When I enter an email address for new outgoing mail, the auto-complete brings up 3 different old, outdated addresses for a couple of the addresses. These are not in my address book, long ago deleted from there, but came from emails I received over time from these people and they no longer use these addresses. What file can I delete, or edit, to remove these? Thanks for your help.

You did not say which web browser you are using (Edge, IE11, Chrome, Firefox, etc.).

Possibly useful link:

https://productforums.google.com/for...4/45hy7TqBcJMJ

Ouch! I knew I missed putting that in. I use Firefox.

Did you try it in other browsers? That would determine if it's a Gmail or Firefox problem.

Did you check your Gmail contacts to make sure there are no duplicates?

In looking at the link given in a posted reply, I discovered the issue is in Gmail Contacts. There is a group "My Contacts", and here is where I add contacts I wish to have permanently. But I noticed there is another group named "Other Contacts," and when I opened that group, here most of the contacts have no "name", only the email address and the email address is in many of the also shown under "Name." I think these must be contacts I have used, for instance, in replying to a real estate broker when I was inquiring about a home, or some other address that has been used only once. There is an old email address of mine I have not used in 5 years. There are over 400 here, and I think this is the file I am need to edit and delete. Many of these are duplicates from the main list,"My Contacts". Many thanks for your assistance.

I believe there's a setting in Gmail to automatically enter contacts who have written to you. You have to uncheck that box.

Yes, there is a setting. I forgot about that. The actual wording is:
"When I send a message to a new person, add them to Other Contacts so that I can auto-complete to them next time"
Now that I know how the "Other" contacts are created, I can clean them out from time to time. Thanks for reminding me of that.