Nancy Jones, 79, thought she knew what materials could be recycled. Then, she read an article about recycling in The New York Times.

Now, she’s not so sure.

“There’s so much information out there,” the 12-year Claremont resident said. “I just try to do my part. But it’s hard.”

And if it’s not a problem of too much information, then she runs into the problem of not enough.

Ms. Jones has had trouble finding any information on how to dispose of gel packs that come in the mail with her husband’s diabetic medication. She said she’s called several businesses and even asked at an Earth Day event. But, no one gave her a sufficient answer.

“I try to be a good person,” Ms. Jones said. “[But] I don’t know if I’m doing the right thing or not.”

Kristin Mikula, Claremont’s community services manager, wrote in an email that the gel packs cannot be recycled and need to go in the trash. Acceptable recyclable materials vary by city.

For Claremont, paper recyclables include envelopes, magazines, cardboard boxes and milk cartons. Glass and plastic bottles and jars are recyclable once thoroughly washed out, and so are aluminum cans.

Styrofoam of any kind is not recyclable. Neither are plastic grocery bags or waxed paper. The full list of recyclables and non-recyclables can be viewed on the city’s website.

But, not all Claremont residents are aware of the list’s existence, and some who have seen it are still unclear about whether certain materials are recyclable. This ambiguity results in “aspirational recyclers,” who put materials in the recycling container they want to be recyclable—regardless of whether they actually are.

Denise Spooner, 63, is a self-described aspirational recycler.

“I do it without realizing that it can ruin a load,” she said. “I don’t want what I’m doing to ruin a load.”

Greasy pizza boxes and disposable coffee cups are additional non-recyclable items that often get thrown into the recycling bin, according to The New York Times. Items like milk jugs and yogurt cups that aren’t fully washed out can also ruin a recycling load through contamination.

For Mark Merritt, 62, the uncertainty about what to recycle keeps him from recycling as much as he could.

“It’s raised a doubt in my mind,” he said. “I worry about contaminating things [… and] it’s better to err on the side of caution.”

Specifically, Mr. Merritt is hesitant about recycling bottles that contain oil and cardboard milk containers. Additionally, he said he’s unclear on what plastics are recyclable.

“I’m sure the city has tried to make it clear, but I’m not certain,” he said.

Following residents’ efforts to properly sort their recyclables, what happens to the materials, anyway? Ms. Jones, who lives in a condo in Village West, said a few months ago she saw a trash truck back up to the trash bin at her complex and pick up the trash. Then, it appeared to back up to the recycling bin and dump the contents on top of the trash. 

“This seems a bit of a disconnect to me,” Ms. Jones wrote in an email.

Ms. Mikula explained that “trash and recycling are picked up in separate trucks and taken to separate facilities.” The only exception, she wrote, would be if the driver thought the recyclables appeared contaminated. To prevent contaminating the entire load, the contaminated container could be picked up with the trash.

It’s unclear if the recycling load Ms. Jones saw getting picked up was contaminated.

Jay Ware, general manager for Ware Disposal, acknowledged that recycled materials do sometimes get contaminated.

“Contaminated recyclables is a constant challenge in our industry, but for the most part people are educated on what is recyclable,” he wrote in an email.

Claremont City Councilmember Larry Schroeder echoed Mr. Ware, explaining that Claremont’s recyclables “typically have low levels of contamination,” in an email to Ms. Spooner June 6.

The city also consistently receives “positive feedback” on the quality of its recyclables from Azusa Reclamation, the site where Claremont’s recycling is brought and processed, Mikula wrote. After being processed, some materials are shipped to foreign countries. But, perhaps not for long.

On January 1, China implemented a ban on importing various types of plastic and paper and tightened standards for materials it doesn’t accept, according to The New York Times.

Reflecting on these changes, Mr. Ware wrote that “recycling will become much harder and more expensive in the upcoming years and less products will have recyclable value making it more difficult to recycle and require less contamination.”

To increase the value of its recyclables, the city of Claremont is developing new marketing materials to ensure contamination rates stay low, according to Mr. Schroeder.

“The impact of these global market changes will be felt locally,” he said.

In the meantime, Ms. Jones remains confused about what to recycle even after reading the city’s list.

“I’m wondering if anything should go in the recycling anymore,” she said.

—Meghan Bobrowsky