In the united states, what material is least likely to be recycled?

The material that is least likely to be recycled is the PET plastic or also known as the Polyethylene terephthalate plastics that are used in beverages or condiments. It is because though it is convenient and could be recycled after using, the residue that is left in it is hard to remove, making it difficult, time consuming and expensive to be recycled that is why it is least likely to be recycled.