Do not touch uninsulated dry ice with your bare hands. Your dry ice should fully dissipate within 24 hours of delivery. After putting your mylk in the freezer, place the insulated bag (with the dry ice still inside) in a well-ventilated area until any remaining ice has disappeared.
Be sure to keep the dry ice out of reach of children and animals, and don't place it on any tiled or solid surfaces (like in a sink), as it can cause severe damage. Once the ice has dissipated, you can recycle the box and insulated bag.