つめのあかをせんじてのむ

爪の垢を煎じて飲む

to take a lesson from (someone serving as an example); to learn from someone's example; to boil the dirt under (someone's) fingernails and drink it

N3Expression
Expression, Godan verb (mu ending)
to take a lesson from (someone serving as an example)to learn from someone's exampleto boil the dirt under (someone's) fingernails and drink it