Fry: Sorry, I'm not here to buy.
Car Dealer: I understand, and it's wonderful that you don't care whether anyone questions your sexual orientation.
Fry: I care! I care plenty! But I just don't know how to make them stop!
Car Dealer: One word: Thundercougarfalconbird.
As others have said... slowly is how you do it. Every time you get an email at the gmail account, update your address with that account. In time you'll get fewer and fewer things there until one day you're done.