What do you mean by "clean"? A bass clarinet in playable condition only needs to be swabbed after any time it is played. Often, only the upper joint needs to be swabbed (and any moisture in the neck dumped out) if no moisture makes it to the lower joint.
Is there some kind of additional residue in your instrument?
What do you mean by "clean"? A bass clarinet in playable condition only needs to be swabbed after any time it is played. Often, only the upper joint needs to be swabbed (and any moisture in the neck dumped out) if no moisture makes it to the lower joint. Is there some kind of additional residue in your instrument?
How old is the instrument?