When a Kohen performs the kemitza, the presence of a pebble, a grain of salt, or a shard of frankincense within the handful renders the offering invalid. This is because the Torah requires a precise "handful," and these foreign objects either displace the necessary flour (making it "missing"). The Gemara explains the need for the Mishna to bring all these examples. Rava explains that kemitza is performed with all five fingers. Abaye questions this from a braita that explains the need for all five fingers, as can be seen from the name of each of the fingers. The fourth finger is called kemitza, implying that only the three middle fingers are used for kemitza. To resolve this Rava explains that all five fingers are used but not all for the scooping. The kohen extends his three middle fingers over his palm to gather the dough, while simultaneously using his thumb and pinky to level the scoop by wiping away any excess flour protruding from the edges. This ensures the volume is exactly the capacity of his palm. This is one of the most difficult actions to be performed in the Temple, among them melika and chafina.

Rav Papa questions whether non-traditional methods - such as scooping with the fingertips facing down, or in other atypical ways, are valid, ultimately leaving these queries unresolved. He also questions different methods of chafina of the incense that the kohen gadol does on Yom Kippur. Rav Papa and Mar bar Rav Ashi question atypical ways of placing the kometz in the sanctified vessel. All these questions are left unresolved.

If there is too much oil or too little added to the mincha offering it is disqualified. There is a discussion about how much is too much and in what cases does it disqualify. Regarding the frankincense (levona), there is a dispute regarding the minimum amount required for the offering to remain valid. Rabbi Meir holds that a full handful must be present, while Rabbi Yehuda and Rabbi Shimon allow for a reduction to two granules or even a single granule, respectively. There is a debate about whether these three opinions are only relevant in frankincense brought as a supplement to a meal offering or also when the frankincense is brought as its own offering.

The validity of the meal offering is also tied to the kohen's mental intent (machshava). If the kohen intends, while taking the kometz (parallel to the act of slaughtering an animal) to eat the remains or burn the handful of the meal offering or the frankincense outside the Temple courtyard, the offering is disqualified but does not carry the penalty of karet. However, if he intends to consume or burn the offering outside its designated timeframe (the following day), the offering becomes pigul. This status not only invalidates the sacrifice but also makes anyone who eats it liable for the punishment of karet.