The technique to retrieve the microwave permeability of metals from the measured constitutive parameters of composites with fine powder of these metals is developed. The technique is based on the modified Sihvola mixing rule and describes a wide range of contrasts in the component susceptibility, accounts for both the inclusion shape and the percolation threshold. These parameters are related to the Bergman-Milton shape-distribution width and to composite structure. The technique is applied to retrieve the microwave permeability of nickel. The metal permeability is calculated from the measured permittivity and permeability of paraffin-bound composites filled with nickel flakes or spheres with account for skinning in conducting inclusions. The measurements are performed using the transmission coaxial-cell in the frequency range up to 15 GHz. The effects of filling factor, inclusion shape and size on the retrieved permeability spectra are analyzed. The permeability retrieval procedure is based on parameter fitting of the selected mixing model for the measured permittivity and permeability data. The retrieved permeability is close to the data available from archived literature sources that are obtained with thick nickel wires and foils.