This pen cleaner solution by Higgins removes dried waterproof ink from dip pen nibs and makes a wonderful cleaner for fountain pens and brushes. We've especially loved it to flush out the Noodler's Konrad flex fountain pen.
To use, decant a small amount into a jar and immerse nibs anywhere from 30 minutes to 8 hours. To flush a piston-mechanism fountain pen or cartridge converter, simply fill the pen with the cleaner, as you would with ink. While you can re-use the solution once or twice, it's best to discard it once it's been used.
Sturdy plastic bottle with screw cap, contains approx. 74ml.