Recycling 101: How clean does recycling need to be?

Is Your Pizza Box Recyclable?

Recycling is an important part of building a circular economy, but we don't want to waste excess water or power when rinsing our materials for recycling. There are a few key considerations when it comes to how well something needs to be rinsed before it hits your recycling bin:

• Can it be rinsed?

• Will the remaining contents contaminate other recyclables?

• Will it become a health and safety issue for people who manually sort waste?

• Will it attract pests?

We will dive into these considerations below. The short answer is you want to gently rinse to remove all food remnants and liquids and leave out paper or card with oils embedded in it.

Cleaning Recyclables: Rules of Thumb

Here are a few rules of thumb when it comes to cleaning recyclables:

• Scrape out thick contents like peanut butter.

• Use a small amount of water to rinse out milk bottles.

• Shake sauce bottles/jars with some water (lid on).

• Around a teaspoon of water remaining in bottles is fine.

• Thicker, oil-based liquids like mayonnaise should be completely removed.

• Paper or cardboard with grease or other liquids isn't recyclable.

• Where possible, rinse with dishwater you're already using to avoid excess water waste.

While cleaning your recycling is important and can reduce contaminating other recyclables, we still want to avoid wasting other resources in the process. That's why we recommend rinsing in leftover water from washing dishes where possible, using cold water and avoiding unnecessary soap.

As paper and cardboard are fibrous, they can't be rinsed to remove food or liquid contaminants, so the question becomes, is it clean enough for recycling? Paper with grease, wax, or other liquids embedded in it cannot be recycled. These can't be removed in the recycling process; they can damage machinery and ultimately result in a lower-quality recycled paper output.

So, the question about pizza boxes? No, if they are greasy or have food embedded in them, they can't be recycled. Cut off clean cardboard and recycle that, compost, or throw away any contaminated card.

Contamination Concerns

Hard materials like plastic, tin, or glass can be easily and effectively cleaned in the recycling process. However, paper and cardboard are fibrous and absorb oils and liquids they come into contact with, making them lower quality or no longer recyclable. So when you're recycling something that contains an oily substance, in particular, make sure the remnants aren't liquid enough to mix with the other recyclables. A good example of this is curry in plastic containers; so long as you remove any loose sauce, this is fine to go in your recycling bin - you don't need to scrub it clean.

Health and Safety for Waste Sorters

Each Material Recovery Facility (MRF) where recycling is organized before it goes for processing has a different way of going about it. While they are becoming increasingly automated, many still involve people - from manual sorting to those controlling the systems. So be considerate of those who keep our waste processes moving; no one wants to come face-to-face with a milk bottle that still has milk in it that's been sitting around for days in the sun. Not to mention that many MRFs report receiving dangerous goods within recycling, from nappies or batteries to needles.

Pest Attraction

Ultimately, ensure you're not putting food remnants, liquids, or dangerous goods into the bin - in hard containers or embedded into paper. Avoid wasting water or electricity where possible, and consider the people who sort the waste.