פירוש על מעילה 2:5

אין מועלין בבשר – for there is a period of availability for the Kohanim, for the meat of the sin-offering and guilt-offering and communal sacrifices of peace-offerings, are consumed by the Kohanim.

The law of sacrilege applies to the hatat, and asham and to shelamim sacrifices of the congregation from the moment of their dedication.
Once slaughtered they become susceptible to be disqualified through contact with a tevul yom or one who still requires atonement, or by remaining overnight.
Once their blood has been sprinkled they are subject to [the laws of] piggul, notar and defilement.
The law of sacrilege then no longer applies to the flesh, but applies to the innards until the ashes are removed to the place of the ashes.
This mishnah refers to other most holy sacrifices, namely the hatat, the asham and the public shelamim sacrifices. These are the two lambs sacrificed on Shavuot. They are considered most holy sacrifices, although other shelamim sacrifices are sacrifices of a lesser degree of holiness.
Sections one-three: See the previous mishnayot.
Section four: Once the animal has been slaughtered, the flesh may be eaten by the priests, and therefore the law of sacrilege no longer applies. However it continues to apply to the innards until they are burned and then brought out to the place of ashes.

אבל מועלין באימורים – for there is no period of availability for the Kohanim.