Caps On or Off for Plastic Bottles: What's the Best Practice?

It's a common question with a surprisingly complex answer: when storing or recycling plastic bottles, should you leave the caps on or take them off? The best practice depends on the context—whether you're storing a product or preparing the bottle for recycling.

For Product Storage

When storing products in plastic bottles, it's almost always best to keep the caps on and tightly sealed. Here's why:

• Prevents Contamination: A sealed cap protects the contents from dust, bacteria, and other environmental contaminants.
• Maintains Freshness: It prevents air from entering, which can degrade the product, especially for sensitive formulations.
• Avoids Spills: A secure cap prevents accidental leaks and spills, which is crucial during transportation and storage.

For Recycling

The advice for recycling has changed over the years. Previously, it was recommended to remove caps because they were often made from a different type of plastic than the bottle. However, many recycling facilities now have advanced sorting technology.

The current recommendation from the Association of Plastic Recyclers (APR) is to leave the caps on. Here's the reasoning:

• Caps Get Recycled: Modern facilities can separate the caps and bottles during the recycling process. The plastics are ground up, and the different types are separated in a water bath (e.g., PET bottles sink while PP caps float).
• Prevents Lost Caps: Loose caps are often too small to be sorted correctly and can end up in landfills. Keeping them on the bottle ensures they make it through the sorting process.
• Reduces Litter: More caps get recycled, leading to less plastic pollution.