The depolarization of a neutron beam passing through a system of magnetically misaligned single domain particles is examined and simulated using a Monte Carlo program. The results of the simulations are in excellent agreement with those of analytic calculations within the regimes where such calculations are applicable. The simulations have been used in the estimation of the polarizing efficiency and transmittance of a resonance absorption filter containing partially aligned particles of SmCo5. It is shown that the application of strong magnetic fields (∼2 T) should significantly improve the filter performance. A method of measuring this improvement is suggested.