It is extremely difficult to delete old email addresses from yahoo mail. I try deleting them from contacts but they don't stop autofilling.
It is difficult to remove obsolete email addresses from Yahoo mail. Deleting them from contacts doesn't make them go away. Clicking on the "X" to the right of an autofilled email address sometimes deletes them but often will not. It is terrible because for some people I have 5 or 10 obsolete email addresses that autofill and I can never find the correct email address. Yahoo should make it easier and more intuitive to delete old email addresses that are being autofilled.

Hi there,
Could you please message us on Twitter at @YahooCare or on Facebook at Yahoo Customer Care? We'd like to look more into the issue you're experiencing. In case you do not have a social media account, we are also available at: help.yahoo.com
Looking forward to your reply!
Thank you,
Yahoo Mail team