My ex-maid washed some red packets with $100 notes still inside shirt pockets. The red packets were already dissolved and gone but the $100 notes were still perfectly okay. So if your maid doesn't return it to you, there is high chance the she has kept it.
Give her a chance to ask her if she finds something left inside the pockets (don't mention that it is money) to see if she will give it back to you. If not, you can give her up.