I never leave home w/o one.I know some old-timers that still cary a kerchief. I like the idea, but a part of me thinks it's gross.
Twice used one in a medical emergency: (1) to stop the bleeding of a friend's headwound after he fell off a ladder -- then jammed it between his teeth when he went into a grand mal seizure; and (2) to clear the airway of a neighbor on whom my dad and I performed CPR. (Both lived; neither complained.)
Sometimes I'll even carry a spare (mostly to funerals where Mrs. MAG40 or some other lady finds herself in need).
A friend who attended my Mother's funeral said it looked like we had choreagraphed it when, after the soloist sang Ave Maria, my six brothers and I simultaneously leaned slightly to the left, withdrew our handkerchiefs from our rear right pockets, blew our noses, leaned slightly to the left, and returned them to our pockets. (All of us laughed hard after hearing that.)