From OpinionCamp > Polls you can clear a poll’s votes or remove a poll completely.
Resetting removes all the votes from a poll but keeps the poll itself, with its question, choices and design. Use this after testing a poll, or when you want to ask the same question again from zero.
Hover over the poll in the list and click Reset Results.
Deleting removes the poll and all of its votes for good. Hover over the poll and click Delete.
Both actions cannot be undone, so you will be asked to confirm first.
Tick the boxes next to the polls you want, choose Reset results or Delete from Bulk actions, and click Apply.
Just want to take a poll off a page for now? You do not need to delete it. See How do I retire a poll and bring it back later?