This is a quick thing. Hard to find unless you know where to look. When running a CoreData driven app, there are times when you’d like to just rest your data store and start again. Doing a schema change is one such case. Of course if you’re doing something really silly and mess up the data, again.. reset!
So, to do that, simply delete the .sqlite file for your app. Running in the simulator, that is stored in your home directory under ~/Library/Application Support/iPhone Simulator/User/Applications/<special app id>/Documents/<appname>.sqlite
Easy, huh? Deleting this is sure nicer than clearing all apps and data from the simulator.