In one aspect, methods of post-processing an object made by additive manufacturing are described herein. In some embodiments, a method of post-processing an object described herein comprises providing the object in a microwave absorptive state and exposing the object in the absorptive state to a field of microwave radiation. In some cases, providing an object in a microwave absorptive state comprises heating the object, including by non-microwave heating. Moreover, in some embodiments, the object is exposed to a uniform or substantially uniform field of microwave radiation in a microwave cavity. In addition, in some instances, exposing an object to a field of microwave radiation in a manner described herein comprises increasing the density of the object and/or reducing the volume of the object, including in an isotropic or substantially isotropic manner.