I just got my replacement Droid and will be sending my current Droid back to Motorola. I'm sure they are going to refurbish it and resell it. I've backed up everything and I'm going to be keeping my microSD card, but how to ensure that all the data is completely wiped off the internal memory so there is no chance that it can be recovered by someone else?

today I got an old HTC Magic phone with OpenEclair (Android 2.1-update) installed on it. Unfortunately there is still the Gmail account of another person linked with it, which I'd like to remove. However, for doing so, you need to do a "factory reset" on the phone. So did I, the phone rebooted, but the data (apps, settings and the account) was still there. Nothing had been removed! Anyone has an idea what could be the problem and how to …