Gasping Snakes!?

My 2 Boas have had breathing problems for about 2 months now. Its not serious they just have trouble breathing. I think there noses are plugged if so how do i get the gunk out? Also the sometimes exhale really loud like a loud hiss but they know its me and there not the least bit aggressive. Its not star gazers disese either they dont do that. They still eat fine too. I looked in there mouth and no signs of mouth rot at all. Plz help!! its not very humid in my house is that the problem?? Both boas are in the same cage and only they got it. Help!!