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Plastics Explained


What changed? 

  • BOTTLES AND TUBS are the ONLY plastic items that can be recycled with MSU as of fall semester 2021.
  • If a plastic item is not a bottle or a tub as described below, please keep it out of the recycling bin.
  • There is no need to look at what number is on the plastic item, as this does not determine whether or not it is an accepted item.
  • (The guidelines for all other types of recyclables remain unchanged. See Recycling Guidance for other materials you can recycle with MSU.)


  • There is strong and consistent market demand for certain plastics, while other types of plastics do not have reliable markets. While we previously could market a wider variety of plastics, MSU currently only has reliable markets for plastics that are used to manufacture bottles and tubs used as packaging for food and beverage, cleaning supplies, toiletries, and other commonly used products.

What's the benefit of the change?

  • This change will help ensure that plastics accept at MSU are recycled into new products.

 When are the signs being updated?

  • Signage updates are currently underway on campus and will continue until all waste and recycling stations have the updated sign that reflects the new guidelines. 
  • The public MSU Recycling Drop-Off Center will be updated to reflect these changes in mid-September. Please continue to follow the guidelines listed on the signs.


  • What plastic items can I recycle?
    • You can recycle plastic bottles and plastic tubs.
  • Does it matter what number the plastic is?
    • No, there is no need to check the number (resin identification code).
    • See more info below, under the section "More about Plastics."
  • How do I know if it is a tub?
    • A tub is a container that may be circular, oblong or square.
    • It may have an unattached snap-on lid or cover.
    • Examples: butter, sour cream, cottage cheese, dairy or whipped topping, or fruit and yogurt cups.
  • How do I know if it is a bottle?
    • The neck of the container is smaller than the body of the container.
    • Usually contains liquids.
    • Examples: water bottles, milk jugs, soap bottles. 
  • What about plastic bags and pouches?
    • Plastic bags and pouches cannot be recycled with MSU currently.
    • However, many grocery retailers have collection points for plastic bags.
    • We suggest checking with a grocery store, such as Meijer or Kroger.
  • What is a "clam-shell?" 
    • A clam-shell is a term used to describe a plastic container that has two halves joined by a hinge area which allows the structure to come together and close, like the shell of a clam.
    • Typically used to contain fruits, salads, etc.
    • See more info below, under the section "More about Plastics."
  • How can I tell if it is a clamshell or a tub?
    • Typically a clamshell has a "hinge" of plastic that holds together the top and bottom pieces. Other markers that help you identify it as a clamshell include: Is it odd shaped (not circular or square)? Does it have ridges or holes in it? If you answer 'yes' to either of those, the item is likely a clamshell and should not be put in the plastics recycling bin at MSU.
  • Other than the shape, is there really any difference between tubs and clamshells?
    • Yes. In terms of composition, clamshell containers can be made from a variety of plastics including polystyrene, PET, PVC, etc. Most recycling sorting facilities cannot correctly sort them out (including ours). In addition, clamshell containers are made from a process called thermoforming whereas bottles and jugs are made by blow molding. These two different processes result in different grades of plastic material that have their own specific uses. Plastics made from these different processes cannot be easily mixed/recycled together.
  • Why are tubs accepted but clamshells are not?
    • The majority of tubs are made of Polypropylene. There is and has been a consistent market for this material so we can be confident that if we accept it, we will have a vendor who will purchase it from us and that it will get recycled.  There is not a consistent market for clamshell containers, and we do not have a vendor who would purchase it from us.  Because of this, we cannot be confident it will get recycled.
  • So for the items you're not recycling now, did you always throw them away?
    • No, we only throw away material that is listed as unaccepted in the bin. We also throw away material that is contaminated (i.e. a peanut butter jar that still has peanut butter in it. See below for more info on contamination in recycling.)
  • How come other places accept more variety of plastics.
    • Other places may have access to markets that we do not and therefore can accept a wider variety of materials. At MSU, we strive to send our materials to markets here in the Midwest. All materials are sent to domestic processors with the exception of some plastics that we have to send to a Canadian processor for recycling.


Please only put items in the bin that we accept. All plastics must be empty, relatively clean and mostly dry before being recycled. Contamination in recycling bins can happen in two ways, both of which you can help prevent!

1. "Wish-cycling" 

    • Definition: When a well-intentioned recycler puts something in the bin that they hope will be recycled, but isn't actually accepted in the bin.
    • Problems: Increases sorting costs and increases disposal costs.
    • Key to Prevention: Read the sign, access the online recycling guides, and/or contact to make sure you know what is accepted.

2. Sloppy recycling

    • Definition: When an item that is still covered in food, beverage, or another residue is tossed in the bin.
    • Problems: Can downgrade the quality of an otherwise clean stream of recyclables. 
    • Key to Prevention: If the plastic item contained food or drink, you may need to rinse or wipe it out to remove excess/

RECYCLING RIGHT -- Examples of Plastic Items

We understand that recycling plastics can be confusing. Below is a list of additional examples of items that are or are not accepted for plastics recycling. For a simple explanation, please see the basic recycling guides for Campus and the Drop-Off Center

Can I recycle ___________ in the campus plastics bin?


  • Beverage bottles (water, pop, juice, iced tea, etc.)
  • Bottles from most vitamins/pain reliever/other medicine in pill forms 
  • Plastic bottles from most soap, hand sanitizer, shampoo and other toiletry-type items
  • Plastic jars (peanut butter, jelly, etc.)
  • Plastic jars from most condiments (salad dressing, ketchup, mustard, etc.)
  • Large, round canisters for items like coffee, disinfecting wipes


  • NO Plastic utensils
  • NO Straws
  • NO Takout containers
  • NO Bags of any kind (NO snack food bags, grocery bags, shopping bags, sandwich bags, etc.)
  • NO Pouches of any kind (for beverage, food, cleaning supplies, toiletries, etc.)
  • NO plastic boxes with holes (for berries, tomatoes, etc.)
  • NO plastic boxes for items like lunchmeat, cheese, etc.
  • NO odd-shaped plastic containers from items like veggie trays, fruit trays, rotisserie chicken
  • NO frozen food trays
  • NO plastic sleeves from rows of cookies, crackers, etc.
  • NO cellophane/cling wrap
  • NO flower pots/landscape plastics
  • NO rubber items
  • NO foam (Styrofoam)


Plastics are a family of related materials which have different properties and can be manufactured to meet numerous use requirements, often packaging or shipping. There are seven different types of plastic resins as identified by the plastic resin code (RIC). The RIC is typically stamped on a plastic product with a number surrounded by chasing arrows. The RIC does not indicate that the plastic is recyclable or made from recycled material, it simply indicates the type of plastic resin.

In addition to the seven different plastic resins, additives and dyes/pigments are included in plastics to change the properties and characteristics of plastics. Additives are chemical compounds added to improve the performance of plastic. For example, additives can make a plastic lighter, stronger or melt at a different temperature. Pigments are particles added to the resin to give it a specific color – think of a green 7Up bottle versus a clear water bottle.

Even though there are only 7 plastic resins, the combination of additives and pigments means that there are literally thousands of different plastic combinations. This means that not all plastics within a resin code are the same. A water bottle and a clamshell container may be made from the same PET resin but have different additives and therefore different properties. These different properties make recycling them together difficult. The combination of dyes, additives and resins result in thousands of different combinations. Manufacturers cannot combine different types of plastics because of their different properties. These combinations make plastic recycling difficult not only for manufacturers, but for recycling centers that may need to sort them out. They must be carefully sorted by type which complicates the recycling process and increases costs. 

A good example of the challenges presented by plastic properties is the difference between a water bottle and clamshell containers commonly used for packaging fruits and vegetables. Both are typically made from Polyethylene terephthalate (PET) plastic but are manufactured differently - water bottles through a process called blow molding and clamshell containers by thermoforming. These two processes result in different grades of PET, each has a specific use, which makes recycling them together difficult. Because PET bottles have a higher value, the clamshell container is often considered a contaminant when they are mixed together.

Plastics are complex so it is very important for recyclers to know and understand which ones are accepted wherever you recycle. When in doubt, keep it out of the bin to ensure a clean stream of plastic for manufacturers to use to make new, recycled content materials.


Coming Soon: Additional information about the various types of plastics.