Should I store my pen filled with water?
Some pen users are convinced that it is best to store a pen filled with water rather than empty. This is not a good idea, and we have heard of cases where the moisture released has caused severe damage to the pen, its plated trim, and adjacent objects.
There is a stronger case for leaving a pen filled with water if it is a piston-filler with a cork seal; many European collectors maintain that this is necessary to prevent cork seals from drying out and shrinking. Yet cork seals are normally saturated with wax before installation, with an additional superficial application of silicone grease. As long as the grease and wax are present, the cork should not absorb a significant amount of water. Years of exposure to cleaning solutions and detergent inks may eventually wash away the grease and wax, in which case the cork will become water-soaked. At this point the seal may indeed shrink if allowed to dry, but a seal in such a state should really be replaced (or relubricated, if practicable).