What's that fuzziness? Could it be ... disgusting mold? Yuck! That ink wasn't even that old. I have ink older than this and still in good condition. The seal was tight. Maybe, it was very humid that day.
On a sadder note:
Have you checked the price of Gocco? The price for the machines are outrageous! I've even seen people selling their old style, used Gocco's for double than what I paid for mine. Price for supplies have even gone up. I'm kicking myself in the butt for not stocking up awhile ago. To be fair - I've also seen a couple Flickr members selling their used PG-Arts for the price they paid and not raising it high. I really want one. I can't afford to spend $400 on one right now. Especially since Gocco is becoming extinct. If their was a promise that someone is taking it over and supplies would one day become available again ... I'd be more inclined to spend the money.