Number 3, or polyvinyl chloride (PVC), is very diverse. It is used to make records, food wrap, bottles, and piping. However, even in recyclable forms, it is difficult to recycle, so it is rarely accepted by recycling plants.
Number 4, or low-density polyethylene (LDPE), is mainly used for packaging material, as well as squeeze bottles. It is only sometimes recycled, depending on the municipality.