Methods for forming a thermoplastic composition include: polymerizing a high purity bis(2-hydroxyethyl) terephthalate (BHET) monomer with butane diol (BDO) to form polybutylene terephthalate (PBT); and combining from 15 wt % to 98 wt % of the PBT, from 2 wt % to 10 wt % of at least one brightening agent, and from 0 wt % to 83 wt % of at least one additional component, to form the thermoplastic composition. The high purity BHET monomer is formed by a process consisting of depolymerizing post-consumer or post-industrial recycled (PCR) polyethylene terephthalate (PET), the high purity BHET monomer has a purity of at least 95%, and the thermoplastic composition has an L* color value of at least 94.