Milk/suck somebody/something dry Verb + object/complement informal
To take and use all of someone or something, but give nothing in return
Lisa married an old man for his money and then sucked his dry.
You are a greedy and selfish person. You milked your grandmother dry and left her alone.
I would suck the system dry instead of building a new one.
To use all of someone or something that is available in order to achieve something
To take or use up everything from a person, thing, or situation as possible
There is no clear information about the origin of this expression.