A method for cleaning an isthmus of a Eustachian tube (ET) of a patient includes using an instrument. The instrument includes a proximal portion, a distal portion, and a shaft extending therebetween, and a treatment feature disposed at the distal portion. The method includes directing the instrument into an oro-nasal cavity of the patient and advancing at least the distal portion of the instrument into an opening of the ET. The method further includes further advancing the instrument within the ET so that the treatment feature is disposed past, or is coincident with, the isthmus. The method further includes moving the treatment feature relative to the isthmus to clean the isthmus.