A clean nose and normal unobstructed breathing is one of the most necessary pre-conditions for proper feeding of a baby. Any excessive mucus AKA "Booger" may prevent baby from breathing freely and thus affect the feed, especially from mother.
The most usual sign of excessive booger is that you can hear your baby breathe (a little like a piggy sound) or you actually see something filling up baby's nasal passage. Now its impossible to ask baby to voluntarily sneeze for you, and it is not advisable at all to put any foreign object, such as cloth, tissue or earbud in baby's nose to attempt a cleanup. Nasal passage is sensitive area with a lot of veins and it is very susceptible to bleeding if something scrapes against the inner walls of nose. Here comes the baby nose cleaners to rescue.
I came across two types of cleaners, both have a smaller end to be put in baby's nose, first one (Type 1) has a little balloon (to create suction) at the other end, while other one (Type 2) has a long tube with a mouth piece at the end that you need to create suction.
Type 1 seems to be very low on suction and thus I never tried it.
I use the second type and it is quite effective. At first I was a bit skeptical of how much suction to apply. However in order to reduce the suction pressure I use a little piece of cotton between the tube and front nozzle. It has helped a lot of times when my baby was cranky and not accepting bottle or breast milk, and it generally turned out the nose was blocked.
The company says that you need to change the nozzle every time you use it, however that just seems a way to sell additional nozzles. Its plastic and can very well be cleaned by putting it under running water, or using an ear bud.
So if you have a baby with cold or with blocked nose, it is a godsend little device to use.
BE THE BOOGERMAN!!
A short video describing usage (not in English)