PFM Brush

This brush is the optimal diameter to clean-out the sac residue that becomes welded onto the walls of the metal sack protector found inside a Sheaffer PFM snorkel. If you run into the problem where the complete sac won't come out because it is stuck to the walls of the sac protector after you've gotten the sac protector off of the pen and removed the plug, go outdoors and put the sac protector in a shot glass and fill the shot glass with acetone. Don't do this indoors, don't let kids near it, don't get the acetone on yourself or the rest of your pen, and warn anyone that gets near it what you're doing so they don't drink it. Let the sac protector soak for about a half hour, remove it from the acetone, and clean the old (now softened) rubber out with this brush.   Our brushes are all different sizes and are not interchangeable; we've scoured the planet to find the perfect sized brush for each application.