Phonak Una User Manual page 41

Insert the cleaning rod where the slim tube attaches
to the hearing aid and push all the way through the
slim tube and out through the dome . It is not
recommended to submerge or rinse the slim tube and the
dome with water, as there is a risk that a water drop
may become lodged in the slim tube. If this should
occur, it will prevent sound from coming through the
slim tube, and may be harmful to the hearing aid
electronics.
The slim tube and dome should be changed every third
month or sooner if the slim tube becomes stiff or brittle.
Only your hearing care professional should change the
dome. This is to prevent the dome from detaching
from the slim tube during insertion in the ear, which
might result in injury.
41