Chapter 6
Which Materials Can Be Recycled?

Items most often recycled on college campuses include: high-grade office paper, blended office paper or office mix, corrugated cardboard, magazines, newspaper, books, confidential paper, computer paper, chip board, plastic, glass and steel cans, aerosol cans, milk/juice cartons and aluminum. See Chapter 11: Special Materials, Chemical and Hazardous Waste to find out which other materials are recyclable, but not collected as frequently on college campuses. Confirm each material's market stability.

 It is important to be as consistent as possible in terms of which materials are collected in order facilitate education on campus. Additionally, be conscious that there are continual changes in packaging and material composition. It is always amazing to see new products showing up that are made with a mix of materials, turning previously recyclable items into trash items. Save samples of new items to show local brokers in order to determine recyclability as market changes follow packaging changes. 

Aluminum Cans
Aluminum is a highly recyclable material. Its durability makes it a highly desired item for industrial purposes. Therefore, it has a high resale value and aluminum sales are often essential in raising funds to support recycling programs. Plastic bottles are replacing aluminum cans in vending machines, but there is still an abundance of this metal to be collected on a college campus. Aluminum scrap can be shredded, then melted down and cast into blocks to be shaped into new products.

Aseptic (Drink Box) Packaging, Milk/Juice Cartons
Aseptic (drink box) packaging is gaining markets across the country. Check within local paper and plastic brokers to learn if the material is collected in the area. Aseptic packages are composed of three materials. Paper accounts for 80% of the package, polyethylene 15%, and aluminum 5%. [9] These cartons are recycled using a paper recycling process called hydropulping that separates the paper from the plastic and aluminum so that the high-quality paper fiber is recovered for recycling into other paper products. In some cases, the plastic/foil residual can be recycled into high-end plastic lumber products.  

Other types of milk and juice containers are made of paper and wax and do not contain plastic. These can sometimes be recycled as low-grade paperboard. Other recycling programs may collect them for composting, especially if organic materials are being processed at an industrial composting facility.  

Paper is one of the easiest materials to collect and market when establishing a recycling program. (See Chapter 8: Marketing Recyclables.) Paper can be recycled in many different ways. Identifying markets is very important when considering which types of paper to recycle and how to recycle it. For example, one university may be able to recycle a blend of paper that includes high-grade white paper, colored paper, newspaper, envelopes, sticky notes, fax paper, card stock, and magazines. Another university on the other side of the same state, may only be able to recycle paper when it is separated into distinct categories such as white paper only, books only, newspapers only, magazines only, etc. Be aware of market specifications for materials and disseminate information updates to all staff members so that materials are prepared properly for deliveries. This will increase program efficiency and generate the greatest income as the receiving recycling company will have a decreased workload and a higher quality product.  

Plastic, Glass, and Steel Cans
The combination of recyclable commodities is called commingled recycling. See Chapter 9: Commingling and Single Stream Collection for more information about commingling and single stream collection. A common commingled collection for college campuses is called PGS or plastic, glass, and steel cans recycling. Each commodity is described separately below. As always, check with the local market before starting to collect and process these items because there are major differences in how brokers want these materials prepared.                                                           

Number and letter combinations such as #1 PET, #2 HDPE, #4 LDPE, and #7 Other are called resin codes and are imprinted on plastic items in order to identify the type of plastic that is contained in a product. These resin codes were developed by the Society of Plastics Industry (SPI) and are strictly regulated by state law as mixing resins can cause serious manufacturing problems and undermine the efficiency of the coding system. [10] Keep in mind that if a plastic item is printed with a resin code, it does not necessarily mean that the product can be recycled. It identifies the type of plastic, but not its recyclability.  

The most commonly recycled plastics within both campus and municipal recycling programs are #1 PET (polyethylene terephthalate, which is used for pop bottles and is blow molded) and #2 HDPE (high density polyethylene, which is commonly used to make milk jugs). Plastics need to be sorted by type before being remanufactured because certain resins are incompatible in recycling processes. Plastic may be shredded, baled, or chipped before it is shipped to the reprocessing plant depending on the plant's specifications. Plastic resins are then melted and remolded into new products. As of 2007, only 11.7% of plastic containers and packaging was recovered through recycling. [11]  

PET and HDPE, are the only plastics that currently have widespread recycling markets and therefore account for most of the plastics that are recycled. The existence of numerous resins causes obstacles in identifying plastics for recycling and the plastic manufacturing industry does little to establish and stabilize markets for viable plastics recycling. Unfortunately, even when a market exists, plastics undergo a process called down-cycling in which the material has a limited lifespan because it is converted into a lower quality item that can only be recycled a few times if at all. This applies to all plastics recycling including block styrofoam, meat trays, and styrofoam cups.  

Meet with local brokers to determine processing specifications to make materials acceptable to recycling markets. Consider working with the campus purchasing department to choose products that minimize plastic waste. Paper, metal, aluminum, cardboard, and glass are relatively stable in terms of consistency in recyclability. There is a perception that plastics are indeed being recycled and therefore a good environmental choice. An increasing amount of consumer goods are made from and being packaged in plastic. Unfortunately, the plastics markets has never been stable and as the fossil fuels used to create plastics are a finite resource, reduction and reuse of plastics is always preferable to manufacturing new plastic, even if it will be recycled.  

Of note: The plastics industry has been changing rapidly as more companies are wanting to be green and thus creating fossil-fuel free packaging that is plant based but still marketed by the manufacturer as recyclable plastic. Check with local markets to determine the recyclability of these new resins.  Unfortunately, packaging manufacturers are not working with recycling end markets to ensure continued waste recovery of these new materials. 

A mechanical processing system breaks recycled glass into small pieces called cullet. Magnets, screens, and vacuum systems remove metals, labels, bits of plastic, and caps. The cullet is blended with silica sand, soda ash, and limestone. The mixture is melted and blow-molded into new glass containers. It is important to know what kind of glass the industry needs. Check with the local market to find out how to sort and prepare glass for recycling. Glass is commonly collected with plastic and steel cans. If it has to be separated from other materials, remember that cullet must meet four criteria. It should be: 

 Recycling glass reduces energy consumption, raw materials use, and wear and tear on machinery. Ensuring a steady supply of recycled glass, or cullet, has become crucial to the recycling industry's success. Other uses for recycled glass containers include fiberglass and other construction uses such as pipe-bedding and trench backfill in place of virgin rock aggregate and recycled glass sand in place of conventional sand in pool filters.  

Steel Cans, Aerosol Cans
Steel is the most recycled commodity in the world on an industrial scale as well as in the home. [12] In fact, steel scrap is a necessary component in the steel manufacturing process. Tin cans are actually tin-coated steel cans. These are used as containers for food, coffee, paint, and aerosol. Removing lids from cans and flattening them makes reprocessing easier. The tin coating on steel cans is removed with a caustic de-tinning solution through electrolysis. The remaining steel is rinsed, baled, and then sold to a steel mill. The tin is also a valuable ingredient in many products. Remain in tune with the market to find out how to prepare materials for sale.  

Other/Specials Materials
There are many more recyclable commodities. Those listed above are just a few of the most commonly recycled ones on college campuses. Please visit Chapter 11: Special Materials, Chemical and Hazardous Waste to find resources about other recyclable commodities.                                                                                                           


General Information 

Commonly Recycled Materials 

The Earth Works Group “Don't Can It” 

Aluminum Cans 

The Aluminum Association 

Steel Recycling Institute 

Aseptic (Drink Box) Packaging, Milk/Juice Cartons 

Earth 911 “Milk and Juice Carton Recycling Made Easy” 

Eco-Chick “Recycling Does a Milk Carton Good” 

Tetra Pak Recycling 


 Earth Answers: How is Paper Recycled?

Georgia Tech Institute of Paper Science and Technology

Paper Calculator (Environmental Defense Fund)

Paper University 

Plastic, Glass, and Steel Cans  


The Association of Postconsumer Plastic Recyclers 

The Bottle Bill Battle Fact Sheet (Carolina Recycling Association)

EPA Common Wastes & Materials- Plastics 

National Association for PET Container Resources 

Plastics News 

Society of Plastics Industry (SPI): The Plastics Industry Trade Association 


 Earth 911 Glass Recycling 

EPA Common Wastes and Materials- Glass

Glass Packaging Institute

Green Mountain Glass, LLC

 Trivitro Corporation  

Steel Cans, Aerosol Cans  

Steel Recycling Institute 

Other/Specials Materials 

See the Resources section in Chapter 11: Special Materials, Chemical and Hazardous Wastes

College and University Websites Listing Recycled Materials 

Brown University

 Emory University

George Mason University

James Madison University

Middlebury College

University of Colorado at Boulder 

University of Massachusetts Amherst 

University of Oregon 

University of Vermont