Cleaning the lower octave vent

Do I need to remove the octave key first in order to clean the lower octave vent (tone hole) on the body? I have the G2 G#2 issue on my Selmer SAII Alto and this looks like a pretty common issue for Selmer horn due to the smaller size of octave vent opening. Before sending my horn to technician to drill out the vent hole, I want to clean the vent first to see if any improvement. After searching the topic on the forum, I learn that I should use pipe cleaner to clean the vent but I find it almost impossible to reach the octave vent hole from outside. Therefore I am wondering if I need to remove the key first in order to access the vent hole? I am very reluctant to do so because of my shallow experience. Any suggestion? Thanks!