Unlocking Microsoft Word documents

Some Microsoft Word files have become locked and I can't work out how to unlock them so that they can be trashed.

They were files I emailed myself from work (the originals long since deleted with the old work computers) and Microsoft Word help doesn't.

Is there anyway to override the lock and delete them? I now have countless copies in my trash, as well as the original locked documents on my desktop. They're breeding…

Any advice appreciated.