It is the most ill-behaved fountain pen ink there is but it's also the most permanent (which is why Noodler's still makes it and people still buy it). You need

It is the most ill-behaved fountain pen ink there is but it's also the most permanent (which is why Noodler's still makes it and people still buy it). You need a pretty strong bleach solution to get the staining out of anything. Water, ammonia, and other standard ink cleaners won't touch it.