There are a small number of specialized mills who recycle only these cartons. However, the cost of collecting, sorting, storing and shipping to these mills is often not cost effective for most curbside programs. Most plastics are also marked with the chasing arrows symbol and a number 1 through 7. The number is actually a code which identifies the chemical compounds of a particular plastic.
Not all plastics are made with the same compounds. Due to safety and environmental regulations in the USA most plastics recyclers choose to recycle only #1, #2 and #5 plastics.
The majority of the mills willing to process these other types of plastics are often located in third world countries, where there are insufficient protections for workers, no child labor laws and little to no environmental regulations. We choose to recycle our plastics responsibly and only ship to domestic mills.