Quote:
"The plastic recycling charity Recycling Of Used Plastics Limited (RECOUP), issued a paper in September 2018 putting forward some new information. It said: ‘It can be confirmed that plastic caps should be left on plastic bottles for recycling. This reduces the potential for the cap to be littered separately, and when attached to the bottle it also allows the cap (as well as the attached neck ring) to pass through the sorting facility and get to a plastic bottle reprocessor.
‘This approach simplifies the consumer message, removes confusion, and makes it easier for consumers to recycle bottles. A separated cap will not successfully pass through a sorting facility and will go into a residue fraction for landfill or energy recovery.
‘If the cap reaches the bottle reprocessor, they can separate the cap and sell that fraction for recycling. Leaving the cap on does not have any negative effect on the value offered by bottle reprocessors to suppliers of post‐consumer baled bottle material.’ "
Source:
https://resource.co/article/what-should-you-do-plastic-bottle-caps
So leave the caps on!
The machinery in recycling plants removes labels from PET bottles by friction, so you can leave those on too.