How to make 220V Cooling Fan blades not polished?

In addition the use of poor quality cooling fan, in the production of this type of "220V Cooling Fan" due to defects in workmanship, the center of gravity "220V Cooling Fan" on blades may not in the axis, forming a "eccentric", a time long fan of "eccentric" phenomenon will become more serious, it will not only produce noise, serious damage may also CPU. In this regard, can be removed altogether, and then thread hanging from its center position, let it sink still to see which direction to put an end to sink in light grinding wheel a few times, and then tested, has been be "220V Cooling Fan" in a horizontal position and then later be able to install up to.