Torath Kohanim (regular TT source) on the chametz prohibition and the kodshei kodashim status of the minchah remainder.
לא תאפה חמץ — אף השיריים. קדש קדשים היא כחטאת וכאשם — ללמד שדין אחד להם. כל זכר בבני אהרן יאכלנה — זכרים ולא נקבות. כל אשר יגע בהם יקדש — ליקדש כמותם.
Lo te’afeh chametz — af hashirayim. Kodesh kodashim hi kachatat vecha’asham — lelamed shedin echad lahem. Kol zachar bivnei Aharon yochalenah — zekharim velo neqevot. Kol asher yiga bahem yikdash — lehikadesh kemotam.
“It shall not be baked with leaven” — even the remainders. “It is most holy, like the sin-offering and like the guilt-offering” — to teach that they share one law. “Every male among the sons of Aharon may eat it” — males and not females. “Whatever touches them shall become holy” — it acquires their sanctity.
R’ Eliezer #1 (ribbuy) + Custom.
The remainder of the minchah may not be baked as chametz; it is kodshei kodashim eaten only by male Kohanim; and whatever touches it becomes sanctified like it.