NOAA's Marine Debris Blog

Keepin' the Sea Free of Debris!

Cap-on, Cap-off


By: Asma Mahdi

True or False: You can recycle a plastic bottle with the cap on. Answer: Technically, true.

Sports drinks, sodas and even water come packaged in plastic. Most bottles are made of polyethylene terephthalate (PET) – an easily recyclable plastic – and are categorized as “#1” by recycling facilities and waste management. However, what you may or may not know is that most bottle caps are made of polypropylene (PP), which is a different, hard plastic listed under categorized as “#5” in terms of difficulty to recycle. Items like reusable food storage containers are often made with this type of higher-categorized plastic because of its strength and durability.

This pictures shows bottle caps, when not disposed of correctly, can easily become marine debris.

Why is the answer to the question above “technically, true?” Well, although both types of plastics are recyclable, not all recycling facilities can process higher-categorized plastics like bottle caps. One reason being that these plastics, like polypropylene, have a higher melting point. In other words, plastic bottles easily melt at a lower temperature than plastic bottle caps. This can complicate the recycling process.

Processing regulations at recycling facilities vary depending on municipalities. Some facilities have the capacity to sort different categorized plastics while others do not. Ultimately where you live or work determines whether you can keep the “cap on” or have to take the “cap off.”

This can be confusing especially for people who travel. One great resource to find out what can and cannot be recycled is Earth 911, Enter in your zip code and the product type (i.e. “#5 plastic caps”) and the search engine will list whether your city’s curbside program accepts #5, and it will also list what recycling facilities are closest to you if your city does not accept higher-rated plastics.

Avoid the confusion altogether— use reusable bottles to cart your drinks. It’s the best alternative to prevent plastic bottles from ever entering the environment and becoming marine debris, but if you catch yourself with a plastic bottle in-hand, just remember this rule of thumb: When in doubt, take it out!

Check out this recycling card by our partner Ocean Conservancy. To find more recycling tips visit:

Author: NOAA Marine Debris Program

The NOAA Marine Debris Program envisions the global ocean and its coasts, users, and inhabitants free from the impacts of marine debris. Our mission is to investigate and solve the problems that stem from marine debris, in order to protect and conserve our nation's marine environment, natural resources, industries, economy, and people.

2 thoughts on “Cap-on, Cap-off

  1. Thanks for this information. I have been taking off the caps from plastic bottles and throwing them out. I checked my county recycling site and found out that they do not recycle the caps- Somerset County, NJ. I used and found the closest location that recycles plastic caps-a municipality 10 miles away. Whole Foods apparently accepts plastic caps for recycling. I wonder if other markets closer would be willing to start accepting them?

  2. Hi John. Thanks for pointing this out. Try ‘#5 Plastic Caps’ and you should get some results!

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