Cardboard Contamination: What You Should Avoid When Recycling

Recycling is often considered the “golden goose” of the world’s waste problems. We conveniently throw our plastics, bottles, and cardboard into the relevant recycling receptacle, safe in the knowledge that they’ll be whisked away and turned into something new.  

Cardboard contamination is becoming a fast-growing problem, caused, in part, by “wish cyclers” who optimistically pop everything into their recycling, hopeful that someone, somewhere can reuse it.  We have seen a considerable change in direction by both consumers and waste companies. Mixed DMR (Dry Mixed Recyclables) bins are not as common as they used to be. Cross contamination is far more likely to occur when you mix cardboard with other waste for recycling – even with some of the most advanced sorting facilities in the world. Having bins for just one type of waste can help – although a bin lorry can still sometimes sling them all in together and compact the contents. We’d recommend baling the individual waste types as it almost eliminates cross contamination and creates a much higher recycling percentage rate. 

The bottom line is that dirty, greasy, and otherwise contaminated cardboard cannot be recycled and placing such items in your recycling can doom an entire load of otherwise perfectly good cardboard to Waste-to-Energy or landfill sites.  

Here’s the lowdown on how you can play your part to keep your high-quality recyclable cardboard within the circular economy.  

What is Contaminated Cardboard? 

Contaminated cardboard is cardboard that cannot be recycled and includes: 

• Unclean Cardboard – Any cardboard that’s greasy, covered in leftover food or excessive tape, filled with packaging materials, wet or mouldy.  

• Unsorted Cardboard – Where non-cardboard items have been mixed into a batch of recovered cardboard, even if the items can be recycled.  

In both cases, recycling companies find it challenging to process the cardboard and may reject the load completely.  

What Happens if You Contaminate Your Recycling? 

Although cardboard is one of the most recycled materials in the UK – around 3,802 tonnes of paper and cardboard were recycled in 2021 – there remains confusion about contaminated cardboard.  

In the past, contaminated cardboard was less of a concern for developed countries, as foreign importers, such as China, bought low-grade recyclables. However, since 2018, when China enacted its National Sword Policy, increasingly stringent conditions have been placed on shipped recyclables. Nowadays, customs inspectors may conduct a random sample of cardboard bales to check the quality and if too many contaminants are found, the entire shipment may be returned to its source – not only is it expensive for the recycling companies, but also a logistical nightmare.  

As a result of these changes in the global market, demand for cardboard has dropped and coupled with rising energy prices, the value of cardboard recyclables has plummeted by 80-90%.  

In the worst-case scenario, contaminated cardboard may be sent to the incinerator to be turned into energy or diverted to a landfill, as it’s simply too costly or complex to sort through the loads. So, even innocently popping a greasy pizza box in your recycling soon adds up to significant repercussions.  

Can Cardboard Contaminated With Food Be Recycled? 

UK councils now face an interesting dilemma – a trade-off between quantity vs. quality. To encourage recycling, the process must be convenient, so limited sorting rules have been enforced.  

However, it means that cardboard risks being contaminated with various undesirable materials, including food. Paper fibres that are stained food debris cannot be separated from the grease when they’re pulped during the recycling process and consequently, the cardboard cannot be recycled at all.  

How to Check for Contamination: 

With a few easy changes to our habits, we can all play our part to improve the UK’s cardboard recycling track record.  

Oil Residue 

Before you pop your cardboard into the recycling bin or cardboard baler, cast your eye over it for any oil stains or residue. In some businesses, this may be less of an issue, particularly if your cardboard mostly comes from packaging. However, oil-stained cardboard may be a regular occurrence in the motoring industry.  

Hidden Envelopes and Labels 

Check all packaging for sticky labels or plastic envelopes containing delivery notes, which you often find taped to the outside of a box.  

Excess Packaging Tape 

While many companies have switched to cardboard tape, plastic packaging tape remains a problem for recycling companies. Remove any excess tape before putting your cardboard into the recycling bin.  

Unemptied Boxes Filled With Plastic 

Flattening boxes is the best way to make efficient use of your recycling bin, and as you do so, you should remove its contents, such as polystyrene packing peanuts.  

Food Waste 

Dirty cardboard cannot be recycled. After emptying your box of food, check if the insides are stained. If so, cut off the offending section, where possible.  

How Can You Keep Your Cardboard Fresh? 

After you’ve checked for the main culprits, it may take a little effort to remove them. Sometimes, despite your best intentions, you may not be able to fully remove the contaminant. In such cases, cut off the contaminated section of cardboard where you can, because recycling some of the cardboard is better than none at all.   

After sorting your cardboard, it’ll need to be stored in a dry storage place, away from any other contaminants, to prevent it from getting dirty or wet, again.  

Cardboard is notoriously bulky, so it may be a challenge to find enough space to separate and store it. Investing in a cardboard baler can pay dividends as not only does the machine compress the cardboard into a dense block, known as a bale, but its chamber can also act as a temporary storage area for clean cardboard until you’ve collected enough to turn the machine on. Bales are tidier, stackable, and easier to store than loose cardboard. 

Explore Our Recycling Machinery 

Talk to our expert team at QCR, who can advise you on the most effective recycling solutions for your business. Whether you’re looking to buy or rent, we can offer affordable recycling machinery for every medium, be it cardboard, plastic or glass.