Deleting indexes from Zend_Registry and why you shouldn't do it !
Zend_Registry is the implementation of the Registry design pattern in the Zend Framework. It is similar to the $_GLOBALS array in pure PHP, but unlike it, it does not provide a transparent way to unset values at a specified index.
As you will see in this short article, there is a very simple way to do it, but that doesn't mean it should be done.
Read the full article to see how values can be deleted from Zend_Registry and also why than is not recommended.