Reference for Menachot 18:19

ואימא אין מיעוט אחר מיעוט אלא לרבות שמאלית אחרינא כתיב כאן שמאלית ואין אחר שמאלית

The other refers to the case where the remainder had diminished between the taking of the handful and the burning thereof, in which case the remainder is forbidden to be eaten although he may burn the handful on account of it. For the question was raised: According to him who says that where the remainder had diminished between the taking of the handful and the burning thereof he may burn the handful on account of it, what is the position with regard to the eating of the remainder? - Ze'iri said, It is written, And that which is left [of the meal-offering],' but not that which is left of the remainder.

Jastrow