Spoilt ballot papers

30. An elector who has inadvertently dealt with any ballot paper in such a manner that it cannot be conveniently used for voting may, on delivering to the presiding officer the booklet containing the same, and proving the fact of the inadvertence to the satisfaction of the presiding officer, obtain another booklet in place of that delivered up (hereinafter called "spoilt ballot paper"), and the spoilt ballot papers shall be immediately cancelled by the presiding officer.