From Wiktionary, the free dictionary
Literally, “to put one's hand to the dough”.
- IPA(key): /mɛ.tʁə la mɛ̃ a la pat/ ~ /mɛ.tʁə la mɛ̃ a la pɑt/ ~ /me.tʁə la mɛ̃ a la pat/ ~ /me.tʁə la mɛ̃ a la pɑt/
mettre la main à la pâte
- (figuratively) to muck in, to put one's shoulder to the wheel, to get one's hands dirty