With Django (what I am using), you use this command:
manage.py vacuum_indexes

What is nice about the process is that, for each index that has been removed from your index.yaml, it will confirm whether you want to delete it or not. So you get a second chance to make sure you are right. If you delete the wrong index, it’s going to take some time for it to rebuild, and portions of your site could be down.

Why do I need this:
I don’t think you would see a noticeable speed improvement to your data inserts, updates, or deletes by having a few less unused indexes, but it couldn’t hurt. Also you are limited to 100 indexes (as of April 2010) so this how you free them up.

appcfg.py update check failed: EOF occurred in violation of protocol

This error is related to not having the SSL module for python installed. The easy fix is to install it by running “easy_install ssl” from the command prompt. However, using Python 2.5, I received errors and it did not work.

The longer, more involved fix is to compile the SSL module for python. This was a hassle but after about an hour I finally got it working.

Here is the tutorial I used to install the ssl module:
http://beautifulisbetterthanugly.com/posts/2009/aug/19/compile-ssl-115-python-25-or-lower/

I also had to follow the troubleshooting section on this link:
http://wiki.cython.org/InstallingOnWindows
because I did not have the python library file (libpython25.a).

Steps to Add a Developer Email Address:

1. Log in to your Google App Engine Account.
2. Under Administration, click Permissions, and add the email address.
3. Log out, and check for the validation email.

More Info:
This is quite a hassle. I understand the reason is to cut back on spam but not only do you have to have a valid email account but you must create a google account for it.
In my case, I just wanted to send notifications out but I don’t monitor the sender address (but I do include a contact link in the email).
Darn spammers!

1. Download Fake Sendmail for Windows. Unzip the files and copy them into a new folder.
2. Add this new folder to your windows PATH, by right clicking on My Computer -> Properties. Click Advanced Tab -> Environmental Variables. Edit the PATH variable under System variables. Append your path to the end of the string. Do not replace the existing paths, just add it to the end preceded by a semi colon. Ex: “;c:\apps\fakesendmail”
3. In your fakesendmail folder, you must configure the “sendmail.ini” file. You have two choices:
   • Use your own custom smtp server settings (if you have one), by setting “smtp_server”, “auth_username”, “auth_password”, and “default_domain”
   • Use Windows default smtp service by setting “smtp_server” to “C:\Inetpub\mailroot\Pickup” and “default_domain” to “localhost”. This second choice will not send your emails but most likely will store your emails in the “C:\Inetpub\mailroot\Queue”.
4. Open a new command console (must reopen the console to pick up the new path variable). Run the appengine patch from your apps root folder with the following argument:
   “manage runserver –enable_sendmail”

Some Additional Info:
This will resolve the error message “SMTP AUTH extension not supported by server”.

These steps were derived from this google discussion.