I see thanks for your help in creating this thread and answering my question so fast.
I made a mistake getting a HSF that is build in this way. It looks nice and cool and has great cooling performance due to the research I had done before making the purchase.
However, a bad on my part the I did not consider the difficulty in the maintenance process. The shape of the HSF is round and the fins converges to the center, this cause the dust that is stick at the thin gap near the center impossible to be removed even with an compressed air gun. Hope that this method helps to remove the excess amount of dust that is trapped between the fins near the center of the HSF.