EQUIPMENT
    Hand-Crank Rotator
    Centrifuge
   


NARRATIVE
            Insert the centrifuge into the rotator chuck. Loosely pack a piece of clean cotton into the centrifuge tube. Leave at least 1 cm empty space below the cotton. Put a few drops of ink on another piece of cotton and insert it into the centrifuge tube above the first piece of cotton. Insert the tube in the centrifuge and rotate it rapidly for about 30 seconds. Remove the centrifuge tube. Notice that the ink has passed through the first cotton piece, leaving it clean.