I just upgraded my phone and looking to sell my Droid to pay for the upgrade. I posted an ad online and people are asking if I have a clean ESN. I have no idea what that is. I took everything off the phone (pics, etc) and then went to the settings and hit the Restore to Factory settings button. It looked like it wiped the phone clean. When I turned it back on it shows that Android guy to go through the stuff I did when I first got it (setting up GMail, etc). Is there anything else I need to do? I just don't want somebody to go to activate it and it activates on my number.