A method of manufacturing bulked continuous carpet filament which, in various embodiments, comprises: (A) grinding recycled PET bottles into a group of flakes; (B) washing the flakes; (C) identifying and removing impurities, including impure flakes, from the group of flakes; (D) passing the group of flakes through an MRS extruder while maintaining the pressure within the MRS portion of the MRS extruder below about 5 millibars; (E) passing the resulting polymer melt through at least one filter having a micron rating of less than about 50 microns; and (F) forming the recycled polymer into bulked continuous carpet filament that consists essentially of recycled PET.

A method for controlling the temperature of a polymer melt in an extrusion tool includes flowing the polymer melt via at least one flow channel from an input to an output and around at least one temperature-control element in the at least one flow channel. The temperature control element includes a plurality of temperature control units. The temperature of the polymer melt flowing around the temperature-control element is controlled by individually controlling each of the temperature-control units so as to vary a degree of temperature control of the temperature-control element such that a degree of temperature control is controllable to be the same or different at locations throughout the temperature control-element.