A method was developed to investigate the kinetics of extraction of the unbound fraction of rubber compounds and to assess the macromolecular characteristics of extracted species. The results obtained show that the extraction kinetics can be modeled with a simple law. For full compounds a correction for nonrubber extractable ingredients must be applied; but it is demonstrated that compounding ingredients do not affect the bound rubber level of a given formulation, providing that the optimum mixing energy level has been achieved during the preparation procedure and that the compound maturation processes have been completed. Macromolecular characteristics of labile rubber species were analyzed versus extraction; and a simple equation, implicitly referring to a Fickean process, is offered to model the observed effects. It is so demonstrated that the polydispersity of labile species varies during the extraction process and that the largest molecular weight fractions are involved in the rubber-filler interaction, as predicted by theory. Experiments on model compounds allow the effect of both the mixing energy and storage maturation to be studied in detail, and a model that takes both effects into account was developed.