He was filled with 'the milk of human kindness'. [=he was filled with kindness; he was very kind]
They 'milked' [='exploited'] their advantage for all it was worth.
greedy landlords 'milking' their tenants of all their money
(..) Right, boys, you work from dawn to dusk. And don't ask how much it pays. Mama. l waited all day. You got milk? No. The money? Stolen. You spent it on movies? Movies, always movies! (..)1988 Cinema Paradiso