Tractate Meilah - Chapter 2 - Mishnah 8 מעילה פרק ב׳ משנה ח׳

Our mishnah discusses how the law of sacrilege relates to menahot.The law of sacrilege applies to menahot (grain offerings) from the moment of their dedication. Once they have become sacred by being put in the vessel [of service] they become susceptible for unfitness through contact with a tevul yom or one who still requires atonement, or by remaining overnight. Once the handful has been offered they are subject to [the law of] piggul, notar and defilement, and the law of sacrilege no longer applies to the remnants, but it applies to the handful until its ashes have been removed to the place of the ashes.