I enjoy re-saccing the Swan Leverless. Though it can happen it is rare to find the old sac stuck to the sides of the barrel and I cannot think of an instance where it had adhered to the paddle. The ossified sac almost always slides out whole with the assistance of a hooked dental pick. Often the imprint of the paddle runs the length of the sac and you know that the pen was put away with a soft sac and never used again. By contrast, lever and button fillers often require internal scraping and the sac can form a bond with the pressure bar that outdoes many glues.
Some models of Leverless have large pegs to which the sac is attached. With those, the repair is straightforward. It becomes more complicated with the Leverlesses that have small pegs. Those are intended to be re-sacced with a necked sac but I find it impossible to get ones of the right length, so I use straight sacs, No 20 for the smaller ones and No 22 for the big Leverlesses. I apply shellac in the usual way then bind the sac tightly with thread. The thread can be removed after the shellac has cured. Alternatively, if the thread doesn’t interfere with the insertion of the section into the barrel, I shellac it and leave it in place. I have come across old repairs where the sac has been bound with thin wire. That’s a bit excessive, I think.
The process is strangely relaxing. You know before you begin that this is not a job that can be rushed so you might as well take your time and enjoy it. To be sure that the sac has securely bonded to the peg it’s best to leave it for several hours. When all is ready, I push the sac into the barrel with a slim dowel and reset the nib and feed in the section. I get more of a sense of “a job well done” from the Leverless than any other pen.