what cardboard can't be recycled?

“When am I not able to recycle cardboard?” is a question we’ve been asked from time to time.

As an initiative dedicated to promoting the sustainable qualities of cardboard, we always encourage consumers to recycle it whenever possible to reduce waste. Yet despite corrugated cardboard having an impressive recycling rate (more than 80% in the UK), it is important to understand there are instances when it cannot be recycled.

By exploring these limitations, we can gain a deeper understanding of the recycling process and make informed decisions about how to dispose of cardboard responsibly.

Here are some instances in which cardboard is considered unrecyclable…


Food contamination

Cardboard that has been spoiled with food waste, grease, or other substances may not be suitable for recycling due to the potential contamination of the recycling process.

However, it’s not a one-size-fits-all scenario either. As long as the carboard is not fully soaked and the staining is limited to the surface, it can still be recycled.

For example, stains caused by grease on pizza and sandwich delivery boxes, as well as traces of breadcrumbs, sugar, salt, flour, or residual food in emptied boxes or bags, can be tolerated for recycling purposes.

Food waste sitting in the pack (such as free moving food), or food attached to the surface, as well as traces and stains that fully soak the paper, is deemed unacceptable.  Once the packaging has done its job and is ready for disposal, consumers should remove any such loose food, if possible, so that it can still be recycled.


Plastic content

The presence of plastic on a cardboard surface will hinder its ability to be recycled.

Current technology used for standard paper recycling is designed to handle a maximum of 1.5% of non-paper components (including plastic and metals). Anything above that threshold may result in cardboard being discarded.

As a result, cardboard lined with plastic film or two-sided laminates, such as beverage cartons, need to be reprocessed separately from plastic-free cardboard.


Foil and glitter

Speaking of plastic content, foil and glitter are another no-go when it comes to recycling cardboard.

Both have the potential to contaminate other waste during the recycling process, which can result in the final recycled material being rejected.

Any tags containing foil or glitter should be placed with general waste instead of in the recycling bin.



This is a tricky one, as adhesives fulfil an integral role in the manufacture of packaging.

Although standard paper recycling technology is designed to separate and eliminate adhesives throughout the papermaking process, certain adhesives present on tape, labels, and packaging bindings could soften due to the heat involved in the process.

These so-called ‘stickies’ have the potential to remain in the recycled paper, compromising both its performance and appearance, therefore resulting in it being discarded.

For these reasons, it’s important to remove any labels or tape on cardboard packages before disposing of them in the recycling bin.

These are just a few examples of instances in which consumers’ good intentions could be undone by incorrect recycling practices. That is why it is important to empower ourselves with the right knowledge and lead by example, paving the way for a more sustainable society.

To learn more about how to improve sustainable attitudes and practices at home, click here.