The clean propolis powders were obtained by comminuting, ground and sifted with a 40-mesh (0.420-mm openings) sieve. These previous steps were performed without none chemical treatment. 5.0 g of powder was dried by freezing; the dry powder was placed in a previously weighed porcelain crucible and heated (first in a stove at 120 °C, and then in a furnace at 550 °C) for 60 min. Aliquots of the resulting white ashes (200 mg) were weighted and placed in polyethylene boxes, for further analysis.