Plastic cups present a complex challenge within the recycling system, as their recyclability depends entirely on the type of plastic resin used, the cup’s form, and the capabilities of the local processing facility. Even cups made from technically recyclable polymers are often rejected due to their shape, size, or contamination. Understanding the material composition and following precise local guidelines are necessary to ensure a cup has a chance at being successfully recycled.
Understanding Plastic Resin Codes
The Resin Identification Codes (RICs) are a standardized system using numbers 1 through 7, typically found inside a chasing arrows symbol, to identify the specific plastic polymer. These codes were originally designed for manufacturers to maintain consistency, not to signal recyclability to consumers. Each number corresponds to a distinct plastic resin with unique properties, requiring different types to be sorted and processed separately.
The two most widely accepted plastics in municipal recycling programs are Polyethylene Terephthalate (PET) labeled #1, and High-Density Polyethylene (HDPE) labeled #2. PET is commonly used for beverage bottles, while HDPE is a durable plastic found in milk jugs and detergent containers. These two resins form the backbone of most curbside recycling efforts due to their consistent composition and established market demand.
Plastics with codes #3 through #7 are generally more difficult to recycle, and many local programs do not accept them. These codes include:
- #3: Polyvinyl Chloride (PVC)
- #4: Low-Density Polyethylene (LDPE)
- #5: Polypropylene (PP)
- #6: Polystyrene (PS)
- #7: All other plastics, including multi-layer materials and bioplastics like PLA.
While PP (#5) has growing acceptance, especially in durable forms, the other codes often lack the stable market or processing infrastructure required for widespread recycling.
Recyclability Based on Common Cup Types
Common plastic cups used for beverages and parties fall into three main resin types, each presenting unique recycling challenges. Rigid, clear cold drink cups, such as those used for iced coffee, are typically made from PET (#1). Although PET is highly recyclable and accepted in curbside programs when in bottle form, its acceptance as a cup varies. Cups may be rejected because their form factor crushes easily and interferes with sorting machinery.
Durable, reusable plastic cups, often used for takeout containers, are generally made from Polypropylene (PP), marked #5. PP is a flexible, heat-resistant plastic that is harder to recycle than PET, but its acceptance is increasing, particularly for rigid containers.
In contrast, foam cups, commonly known as Styrofoam, are made from Polystyrene (PS), which is #6. PS has a low density and limited market value, making it non-recyclable in almost all standard municipal facilities.
Hard, colorful plastic party cups, such as the red and blue varieties, are often made from Polystyrene (#6) or, less frequently, Polypropylene (#5). If made from #6 PS, they are almost universally non-recyclable in curbside bins. Even if made from #5 PP, their small size and tendency to flatten make them difficult to sort mechanically, often resulting in their removal as contamination.
Preparing Cups for Successful Recycling
Even when a local facility accepts a specific type of plastic cup, consumers must take steps to ensure it can be processed. The cup must be empty, clean, and dry to prevent contamination of other materials. Residual liquid, food, or sticky residue can ruin an entire batch of otherwise recyclable material, lowering the quality and value of the recycled plastic.
A quick rinse is usually sufficient to remove sugary drink residue or food particles. This action prevents the growth of mold and reduces the likelihood of the cup being rejected during the initial sorting stage. Food or liquid contamination is a major reason why technically recyclable materials end up in a landfill.
Non-plastic components must be removed from the cup before recycling. This includes plastic straws, which are too small to be captured by sorting equipment, and paper sleeves or stoppers. Lids should often be left on the cup, especially if made of the same accepted plastic, as this helps the cup maintain its shape and weight during mechanical sorting.
Consumers must avoid “wish-cycling,” which is placing unaccepted items in the recycling bin hoping they will be processed. This practice introduces contamination and increases processing costs for the facility. Furthermore, do not nest or stack cups inside one another. Stacking makes it impossible for sorting machines to identify the material type, causing them to be sorted incorrectly or rejected entirely.
Addressing Non-Recyclable Plastics
Many plastic cups with a Resin Identification Code are technically recyclable in a laboratory setting but are functionally non-recyclable in common municipal systems. This disconnect occurs because local infrastructure often cannot handle the specific form or material. Cups are often too lightweight or small to be correctly identified by optical sorters, or they are too fragile, causing them to flatten and be mistakenly routed with paper.
A major challenge is the lack of stable market demand for certain recycled plastics, especially #6 Polystyrene and #7 “Other” plastics. Without buyers for the processed material, facilities lack the economic incentive to collect and process these low-value plastics. This issue is compounded because virgin plastic is often cheaper to produce than the cost of collecting and recycling the used material.
When a cup is not accepted in the curbside program, alternatives should be considered to prevent landfill disposal. Some specialized drop-off programs or private companies offer mail-back options for hard-to-recycle plastics like #6 PS party cups. If a cup is made from a bioplastic like PLA (a type of #7), it requires a commercial composting facility to break down and should never be placed in a standard recycling bin.
The best solution for non-recyclable cups is to reuse them or seek out manufacturers who use more widely accepted plastics, such as recycled PET. Since most single-use cups currently end up in a landfill, making a conscious choice about the cup material or opting for a durable, multi-use alternative is the most impactful action a consumer can take.