How to manually or programmatically delete a field? I tried creating a field, but my server crapped out halfway with an Internal Server Error due to some spambot attack...

Now, when I try to add the field again, I am getting:


  The machine-readable name is already in use. It must be unique.


I guess some tables were populated in the db. How can I remove these easily?
You can also use drush to run field_delete_field(). Just run:

drush eval 'field_delete_field("yourfield")'