Ok, I am going to post this here so that I know where to find it the next time I desperately looking! I am developing for GAE on windows with eclipse and on windows the google launcher doesn’t have the nice option to delete the datastore before launch that it has on the Mac??!!
So, to clear out or delete your GAE application’s local datastore, open a console cd to your application’s directory (i.e the one that has your app.yaml file), and run the following command:
dev_appserver.py --clear_datastore=yes .
This will launch the app server but first empty the local datastore.