The invention relates to a method for the combined processing of at least two polymer melts selected from the group consisting of (M1), (M2) and (M3), wherein (M1) is a polymer melt comprising a terephthalate polyester (A1), (M2) is a polymer melt comprising a copolyester (A2) on the basis of terephthalic acid, at least one aliphatic, ω-dicarboxylic acid and at least one aliphatic 1,ω-diol, and (M3) is a polymer melt 0 comprising a copolyester (A3) on the basis of terephthalic acid, at least one polytetramethylene glycol and at least one aliphatic 1,ω-diol. The method comprises the alternating processing of the at least two polymer melts into at least one product selected from the group consisting of pellets (P1), fibers (P2), expanded particles (P3), preforms (P4) and articles (P5).