Vulcanizates, to which a curative is added by swelling, can be recured to easily study a variety of aspects of the vulcanization process, such as maturation, reversion, and even how much accelerator remains active as its zinc salt at the end of the cure. In effect, vulcanizates can be viewed as high-molecular-weight model compounds. In this study, we find that recuring SBR/BR vulcanizates, to which sulfur or the sulfur donor, N,N′ -dithiodimorpholine, is added, develops the same state of cure as the same amount of sulfur (or sulfur donor) added for the initial cure. This suggests that exchange reactions occur between crosslinks and the zinc-sulfur-accelerator complex during the cure and that all of the accelerator remains as its zinc salt at the end of the cure. This last result is interesting, since it is not consistent with the current view that most of the accelerator becomes irreversibly bound to the rubber and lost during the vulcanization of polybutadiene rubbers.