If I'm understanding you correctly, I think you want $session->clear( ... ). You can use it to remove a single parameter ( $session->clear('paramname') ), multiple parameters ( $session->clear([qw(paramname1 paramname2]) ), or the entire content of the session ( $session->clear() ).

To delete the session itself, use $session->delete(). Depending on context (in particular in persistent environments like FCGI), you might also need to call $session->flush() after manipulating session contents, in order to explicitly synchronize in-memory with on-disk representation of the session data.

(BTW, I'm assuming we're talking about CGI::Session.)