The British postal service has urged people to put empty potato chip packets into envelopes before mailing them back to their manufacturer.
The rather unusual request from Royal Mail comes in the context of an environmentalist campaign against the use of non-recyclable packaging by Walkers, a PepsiCo (PEP) subsidiary that is the U.K.’s biggest potato chip brand.
Walkers has said it intends to introduce entirely recyclable or compostable packets by 2025, but campaigners say that’s not soon enough, as the company could produce an estimated 28 billion more metalized plastic packets before that date.
The campaign organization 38 Degrees has gathered over 300,000 signatures urging Walkers and other brands to quickly move to recyclable packaging, and some started posting on social media pictures of themselves posting their empty packets back to Walkers’ free return post address.
Which is where Royal Mail has had to step in with its plea for envelope use.
“We strongly encourage customers not to post anything into the postal system which is not properly packaged,” a spokesperson told the BBC. “Crisp packets can’t go through the machines, they are not normal mail items therefore my hardworking colleagues need to manually sort them, which adds to time.”
38 Degrees campaigner Cathy Warren told the BBC that the organization would “update” the thousands of people who are taking part in the mailing drive. Walkers, meanwhile, said it had received some of the packets and would use them “for research.”