When my baby got sick with colds, she looked like a dog. She would breathe through her mouth, so her mouth was continually open and her tongue hanging out. Sometimes she would drool.
It was because her nose was stuffy from the mucus stuck in her nostrils. And since she doesn't know how to blow her nose, she would contend herself with just breathing from her mouth.
Then my sister in law gave me Muconase nasal spray, which she uses on her babies. Muconase is simply the solution of Sodium Chloride or salt in distilled water. There 0.65% concentration in this solution.
This 30 ml bottle comes with a nice spray that when sprayed once, goes right smack in each nostril. Then the hole is massage a while to loosen the mucus then manually aspirated. For bigger kids and adults, they could just blow their nose after each spray.
I did this with my baby and even though she would fuss while the process was going on, it was obvious that she could breathe better afterwards. During the problematic days of her illness, we cleared her nose three times a day until it was reduced to twice then only once a day. Now her nose is so clear. This can also be used just to clean baby's nose.
The only thing though is that baby's should be made to drink water after administration because since this is salt, it could cause sore throat when some of the solution will leach to the throat. And this is highly likely, especially for babies.
But it is a really good product that each parent should have handy.