I'm Facing a problem with Orphaned Terms, 
I cannot delete them from term store management tool under Managed Metadata Service Application.

Is there is anyway to clear it?

I try to delete them using powershell and I get this exception

>This operation is invalid in the Orphaned Terms term set.  The operation failed.

[![enter image description here][1]][1]

  [1]: http://i.stack.imgur.com/pLUZW.jpg