Our excellent pediatrician back in NYC showed us this trick. You need an "adult ear syringe" which is just this rubber bulb but so precious, am looking for one here in HK! Anyway, you take a drop of saline into the bulb, then drop on tiny drop in each nostrril and then with the bulb (ear syringe) you suck the offending blockage out. The adult ear syringe works heaps better than the conventional little bulbs they sell for babies.