EarthTalk: Why plastic caps belong in the trash, not the recycle bin

Mixed plastics lessens the value of the recycled material, experts say – and capped containers can also present a risk to workers.

Dan Smith/The Record/MCT/Newscom
Tops in tops: Lisa Malamed (ctr.) and her sons Max (l.) and Jacob of Tenafly, N.J., collected more than 14,000 bottle caps they will send to a company to recycle.

Q: Everyone knows we should recycle metal, glass, and plastic cans and bottles, but what about all the lids, tops, and caps? I see people recycling plastic bottles, for example, with their caps on, but I’ve always been told to throw them out. Is that wrong?
Stefanie Gandolfi, Oakland, Calif.

A: Many municipal recycling programs throughout the United States still do not accept plastic lids, tops, and caps even though they take the containers that accompany them. The reason is that they are not typically made of the same kinds of plastics as their containers and therefore should not be mixed in with them.

“Just about any plastic can be recycled,” says Signe Gilson, waste diversion manager for Seattle-based CleanScapes, one of the West Coast’s leading “green” solid waste and recycling collectors, “but when two types are mixed, one contaminates the other, reducing the value of the material or requiring resources to separate them before processing.”

Also, plastic caps and lids can jam processing equipment at recycling facilities, and the plastic containers with tops still on them may not compact properly during the recycling process. They can present a safety risk for recycling workers. “Most plastic bottles are baled for transport,” says Ms. Gilson, “and if they don’t crack when baled, the ones with tightly fastened lids can explode when the temperature increases.”

Some recycling programs do accept plastic caps and lids, but usually only if they are off their containers completely and batched separately. Given the many potential issues, however, most recyclers would rather avoid taking them altogether. It may be hard to believe, but it’s true: At this time and in most locales, the responsible consumers are the ones who throw their plastic caps and lids into the trash instead of the recycling bin.

As for metal caps and lids, they, too, can jam processing machines, but many municipalities accept them for recycling anyway because they do not cause any batch contamination issues. To deal with the potentially sharp lid of any can you are recycling (such as a tuna, soup, or pet food can), carefully sink it down into the can, rinse it all clean, and put it in your recycling bin.

Of course, the best way to reduce container and cap recycling is to buy large containers, rather than single-serving ones. Does the event you’re holding really require dozens and dozens of 8- to 16-ounce soda and water bottles, many of which will be left behind only partly consumed anyway? Why not buy large soda bottles, provide pitchers of (tap) water, and let people pour into reusable cups?

The same kind of approach can be taken with many – if not all – of the bottled and canned grocery items we buy routinely for the home. If more people bought in bulk, apportioning out of larger, fewer containers, we could take a huge bite out of what goes into the waste stream.

Got an environmental question? Write: EarthTalk, c/o E – The Environmental Magazine, Box 5098, Westport, CT 06881. Or e-mail:

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