At the following website: http://www.ent-consult.com/sinusitis.html

I read the following ".....Healthy sinuses are covered with mucous
membrane, moist, delicate tissue with microscopic moving hairs called
cilia, covered by thin mucous. The nasal and sinus cilia move back and
forth like tiny oars, constantly moving the mucous to flush the sinuses
and nasal passages. The body is defended against foreign particles and
pathogens in the air we breathe by this constant flushing......"

Question: In a healthy sinus, when nasal and sinus cilia flush the
sinuses, where does that mucous go?