Wondering about the little numbers on your milk container? They identify what the container is made of―and what it will be in its next life.

1. PET (polyethylene terephthalate): Soda bottles; recycled into pillow fill.

2. HDPE (high-density polyethylene): Plastic milk bottles, detergent bottles; recycled into new detergent bottles.

3. PVC (polyvinyl chloride): Take-out boxes, shampoo; recycled into drainage and irrigation pipes.

4. LDPE (low-density polyethylene): Grocery bags, shrink wrap; recycled into new bags.

5. PP (polypropylene): Yogurt containers, bottle caps; recycled into plastic lumber.

6. PS (polystyrene): Packing peanuts; recycled into plastic lumber, cassette-tape boxes.

7. Other: Includes squeezable ketchup bottles and microwavable dishes; these items can’t be recycled.