enhanced performance yarns which are functional alternatives to 100 % petroleum oil based virgin continuous filament yarns , and yarns of natural fibers and methods of making them . the yarns may comprise an inner portion of spun staple fibers of recycled plastic and an outer portion comprising a different material and incorporate highly significant amounts of recycled plastics , particularly post consumer recycled , thermoplastic material such as polyethylene terephthalate which contains medium to high levels of contamination . one embodiment of yarn comprises a core , an inner portion of spun staple fibers surrounding the core , and an outer portion comprising an inner helix and an outer helix .