I recently bought 2 SHEAFFER'S Imperial I pens and I'm trying to give them a good clean but I'm not sure how to take the nibs out or even if it's possible, can anyone advise me please? The pens have different filling systems too, one is the touchdown type but the other I'm not sure of, it looks like maybe a cartridge filler but again I'm not sure. The picture below shows a little of the maroon pens section but I haven't had a chance to take a better photo yet, there's no touchdown plunger so the barrel is one piece which is why I'm thinking cartridge but can anyone tell me what type of filling system it uses? Thanks http://i59.tinypic.com/n6pzy9.jpg