If you're referring to your "Domain" thread, why would you need to remove the poll when it's been closed for quite sometime? IOW, why not just ignore it and continue posting on the thread (if that's something you want to do)? If you have a new poll question, start a new thread.
That said, if you're truly desperate to remove the poll question, the moderator of the forum the poll's located in may be able to remove it for you if you PM her/him with a polite request.