Reference for Menachot 1:2
אַחַת מִנְחַת חוֹטֵא וְאַחַת כָּל הַמְּנָחוֹת שֶׁקְּמָצָן זָר, אוֹנֵן, טְבוּל יוֹם, מְחֻסַּר בְּגָדִים, מְחֻסַּר כִּפּוּרִים, שֶׁלֹּא רְחוּץ יָדַיִם וְרַגְלַיִם, עָרֵל, טָמֵא, יוֹשֵׁב, עוֹמֵד עַל גַּבֵּי כֵלִים, עַל גַּבֵּי בְהֵמָה, עַל גַּבֵּי רַגְלֵי חֲבֵרוֹ, פָּסָל. קָמַץ בִּשְׂמֹאל, פָּסָל. בֶּן בְּתֵירָא אוֹמֵר, יַחֲזִיר וְיַחֲזֹר וְיִקְמֹץ בְּיָמִין. קָמַץ וְעָלָה בְיָדוֹ צְרוֹר אוֹ גַרְגִּיר מֶלַח אוֹ קֹרֶט שֶׁל לְבוֹנָה, פָּסַל, מִפְּנֵי שֶׁאָמְרוּ, הַקֹּמֶץ הַיָּתֵר וְהֶחָסֵר, פָּסוּל. אֵיזֶה הוּא הַיָּתֵר, שֶׁקְּמָצוֹ מְבֹרָץ. וְחָסֵר, שֶׁקְּמָצוֹ בְרָאשֵׁי אֶצְבְּעוֹתָיו. כֵּיצַד הוּא עוֹשֶׂה, פּוֹשֵׁט אֶת אֶצְבְּעוֹתָיו עַל פַּס יָדוֹ:
The grain offering of a sinner and the grain offerings from which handfuls were taken by a <i>zar</i> [non-priest], by a person in mourning [for a kinsman who has not yet been buried], by a <i>tevul yom</i> [a person who has immersed himself that day to purify himself, but who must wait for night-fall to be fully pure], by a person who lacks [priestly] garments, by a <i>mechusar kippurim</i> [a person who is required to bring an atonement offering before partaking in an offering], by a person with unwashed hands and feet, by an uncircumcised man, by an impure person, by a person who is sitting, or one who is standing on vessels, an animal, or his friend's legs - these [offerings] are invalid. If he took the handful with his left [hand], it [the offering] is invalid. Ben Betera says: he should return it and take the handful again with his right. If he took the handful, and a stone or a chunk of salt or a remnant of frankincense came with it in his hand, it is invalid, because they said: one who takes too much or too little [as] the handful, it is invalid. What is too much? If he took a heaping handful. And too little? If he took the handful with his fingertips. How should he do it? Extend his fingers on his palm [and bring the flour with his three middle fingers into his palm].