Metal rubber (MR) has become one of the most popular technologies in many applications including seals, heat shields, filters, gaskets, aircraft engine mounts, and vibration absorbers. Stability of mechanical parameters such as size, stiffness, and damping is required to ensure a reliable product. In the present study, effect of different forming processes on the mechanical properties of MR element is investigated, using vibratory loads and heat treatment approaches for residual stress relaxation. Hysteresis loops and real-time stiffness during each process are measured. Height and static stiffness are also investigated during aging treatment. Dynamic stiffness and damping of all manufactured MR elements is tested based on a dynamic test apparatus. The results show that hysteresis loops become stable after several loading and unloading cycles. Moreover, the combined residual stress relaxation method provides stable size and static stiffness. After residual stress relief treatment, MR maintains the stability of the dynamic properties to some extent.