Plastic Recycling: Codes, Limits, and What Actually Gets Reused

The chasing-arrows triangle is often misunderstood. Here is what the numbers mean and why recycling plastic is harder than it looks.

Plastics are not one material but a family of polymers. The small number inside the recycling symbol (the "resin identification code", 1–7) tells you the polymer type — not whether your local facility accepts it.

The 1–7 Codes

• 1 PET — drink bottles; widely recycled into fibres and new bottles.
• 2 HDPE — milk jugs, detergent bottles; commonly recycled.
• 3 PVC — pipes, cling film; rarely recycled curbside.
• 4 LDPE — films and bags; recycled where drop-off exists.
• 5 PP — tubs, caps; increasingly accepted.
• 6 PS — foam trays; seldom recycled.
• 7 Other — mixed or bioplastics; usually not recycled.

Why So Much Plastic Is Not Recycled

Contamination (food residue), mixed colours, and the low cost of virgin plastic all discourage recycling. Many items are "technically recyclable" but not "economically recycled" in a given city. Flexible pouches and black trays are especially difficult because sensors and sorters cannot handle them well.

Mechanical vs Chemical Recycling

Mechanical recycling melts and remakes plastic — mature but quality drops each loop. Chemical recycling breaks polymers back into feedstocks or oils, potentially allowing true circularity for mixed or dirty plastic, but it is newer, energy-intensive, and still scaling up.

How to Recycle Plastic Correctly

• Empty and rinse containers; leftovers contaminate whole batches.
• Keep caps on bottles (they are usually the same polymer) unless your city says otherwise.
• Drop films and bags at store collection points, not the home bin.
• When in doubt, check locally — rules differ by city.

Related Reading

Compare with metal recycling, learn the basics in Recycling Basics, and use our Garbage Search to confirm whether a plastic item is recyclable where you live.

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