like I said, I use them all the time. I have never tried to push the brush all the way through the nozzle, as they will not fit. I do use one to clean out the back part of the nozzle, inside where the threaded portion is. Don't force them where they do not want to go. Jackie's suggestion of using along bristled paint brush is good for getting out the tip of the nozzle. I also find that gently working an old needle out the tip while holding the nozzle between fingers. I use a little acetone in the nozzle, and turn the nozzle frequently while rubbing the needle in and out. Not much pressure, as I am not trying to damage the thing, just clean it. You do not need to do this often... only when everything else has failed to bring the brush back to normal performance.