If a voter makes an error on their ballot, they may ask for a new ballot. First, if the voter made selections in any contests, ask them to fill in all bubbles in those contests so no one knows who they intended to vote for. Next, write SPOILED in large letters across the face of the ballot. Give the spoiled ballot to the Chief and issue a new ballot to the voter.
If a voter marked outside of the bubbles or made erroneous marks on the ballot, the DS200 scanner may reject it because it is unreadable. In this situation, you would follow the same steps to SPOIL the ballot and issue a new ballot to the voter.
If a voter has repeated issues marking a ballot correctly, you may want to suggest using the ExpressVote accessible marking device.
There is one other situation in which a ballot may be spoiled: If a voter requested a mailed absentee ballot, but then wants to vote in-person on election day. The voter can bring their absentee ballot (marked or unmarked), spoil it, and surrender it in exchange for a new ballot on election day.