Ok I managed to remove half of the deposits. Here are my solutions in case other mommies face the same situation.
Initially I kept soaking cotton pad with hot water and place on the blocked nipple pores, use warm towel and place on my breast, massage, then I pump. However the milk deposits simply refuse to come out. Then I let baby suckle. Trust me, baby's mouth suction is so powerful, more powerful than the pump.
Now there are still blocked nipple pores with milk deposits but the big one is gone (in my baby's stomach, haha). I will let my baby suckle again at the next feed, hopefully they will be out completely.