I have bogus entries in the autocomplete cache for the TO: field in the iPad e-mail application.
How do I get rid of these entries that do not correspond to real e-mail recipient addresses?
i have the same problem and unfortunately i believe the only current solution is doing a restore of the phone. once the phone reconnects to itunes, select set up as new phone and resync your apps and other content over. you will also have to reconfigure all your settings including mail.
There's no way to do it, at least none that i'm aware of. OS X Mail has the previous recipients list that you can edit, but i'm not sure if those changes get synced back and forth or not.
There is an option. On your iPad, go to Settings > General > Keyboard and disable auto-correction.