Idaho Code § 34-1109

No person shall take or remove any ballot from the polling place. If an elector inadvertently or by mistake spoils a ballot, he shall return it folded to the distributing clerk, who shall give him another ballot. The ballot thus returned shall, without examination, be immediately cancelled by writing across the back, or outside of the ballot as folded, the words “spoiled ballot, another issued,” and deposit the spoiled ballot in a box provided for that purpose.