__BlobFileIndex__ fills Datastore Quota

__BlobFileIndex__ fills Datastore Quota

I serialize objects to blobstore in my app, and delete and recreate them whenever they change. I know this is not the best way, but I found that is good way for rapid prototyping. 
Now I am in the phase to use datastore, however I have a problem. My datastore quota is full! :) I did alot of search for the issue, yet here I am.
Appearantly for every blob, __BlobInfo__, and __BlobFileIndex__ kinds keep info about the blob. My problem is when I delete blob, info in __BlobInfo__ is deleted, but not the one in the __BlobFileIndex__
I desperately tried appcfg vacum_indexes, but that did not help as expected.
I use Java platform by the way.
Here are my questions

How can I clear unused __BlobFileIndex__ entries?
What is the proper way to handle this situation to not occur again?

Thank you.
Edit: Woohooo! I now see that I cant delete these unwanted indexes
a) Datastore admin does not list them
b) Manual deletion code throws Exception(java.lang.IllegalArgumentException: illegal key.path.element.type: BlobFileIndex) Since entities starting with double underscore are app engine reserved entities, it doesnt allow me delete it. Guys at google, I AM STUCK 


Answer 1:

You can star this issue to get notified as soon as there’s a solution to this…

Answer 2:

I had this problem, but found a solution:

For anyone trying to delete the BlobFileIndex programatically you can do it thus:

query = datastore.Query("__BlobFileIndex__",{'blob_key': a_blob_key}, keys_only=True)
    key = query.Get(1)
    key_y = key[0]