A new process to clean nanoparticles of platinum obtained by a water-in-oil (W/O) microemulsion without loss of crystalline structure was studied. Polyethyleneglycol-dodecylether (BRIJ(R)30) was the surfactant used for the preparation of the platinum particles. Pt(111), Pt(110), Pt(100) and polyoriented platinum electrodes were used to check the effectiveness of this new procedure. Preliminary results obtained with nanoparticles of platinum are also presented. The voltammetric profiles of platinum particles show the adsorption states associated with (110), (100) and (111) domains. The ratio Pt-SURF/Pt-TOT was found to be 0.1 for an upper potential limit of 1 V and 0.12 for an upper potential limit of 1.5 V.