Replacement of carbon black with waste-derived filler in the composites led to an increase in swelling ratio and a decrease in crosslink density. The largest swelling ratios were achieved by unfilled guayule compound and composites containing 35 phr of waste-derived filler as full replacement of carbon black. Nevertheless, the addition of macro and micro sized TP and ES up to 35 phr (no carbon black) significantly reduced the swelling of the guayule rubber compounds (Table 3). Most of the composites containing micro sized filler had higher swelling ration than macro sized composites at the same loading with the same filler.