Got a beautiful Visconti set with several different nibs, plus glass nib dip pen: just put a cartridge into the nib unit, and it can't have been properly pushed on, as it's now stuck firmly in the barrel. Im hoping to get pliers or tweezers to remove....in UK, I have Amazon Prime, and hopefully can get something by tomorrow, but have no idea as to sizing for such things, so...... .....help! Alex