bzr heads: how to kill uncommited revisions?

[Alexander Belchenko]

I like to use shared repository for development. Especially for my work 
on bzr.dev. I often uncommit revisions. Or simply delete wrong way branches.

Now I have 'heads' plugin that able to show all revisions that don't 
have childs. And it show all uncommitted revisions too. So I suppose 
that uncommitted revisions don't deleted from shared repo (may be it's 
true and for standalone branches).

Is there exist way to actually kill unnecessary heads?

--
Alexander