Don't cut up your plastic milk jugs! I wash them out and then use them for storage. It's much easier to pour powdered milk from the plastic jug than the large cardboard boxes and I can see how much I have left. Prevents running out when I need it for a recipe. I also use the jugs to store dried beans that I buy in bulk (cheaper), elbow macaroni, sugar, flour, and corn meal.. The handle really makes the jobs easier.
This is a nice way to reuse a milk jug to help keep your extension cords tangle free. This page shows you how to make a milk jug electric cord reel.
A cut down milk jug makes the perfect scoop for dog food or other dry goods. This is a page about making a scoop from a quart milk jug.
This is a page about using milk jugs in the garden. Plastic milk jugs have a variety of uses in the garden.