Nokia :: 6303 How To Delete Email Have Downloaded / Always Waiting For Deletion?

use my nokia 6303 for checking email (gmail / eircom email). Have set-up and works fine - i.e. I can download and read email on my phone.problem is that when I say delete from phone and server it tells me that it is waiting for deletion and never seems to diappear as an entry on my phone. Does anyone know why this is and how to delete these entries from your phone? Do these waiting for deletion entries take up much space on your phone ?