1. To deprive completely of money or goods.
2. To empty completely; SYN. clear out.

[informal] When people clean you out or clean you out of your money, they deceive you or pressure you into giving them all your money or spending all your money for their benefit. When an expense cleans you out, it requires you to spend all your money.
When you clean something out, you clean the inside completely so that no dirt, dust, trash, and so on, remains inside.