I grabbed a cotton shirt (belonging to my husband, naturally) and splashed on some Panthers Black. I let it sit for a bit.
Cold running water rinsed away some of the dye, but not enough.
I took out my secret weapon. Okay, actually just a laundry product. But a good one. Notice I have the 7.22 pound size.
I soaked the stained shirt in a little hot water with OxiClean. And a few minutes later, the stain was completely gone.
That’s good washable black ink. It’s Seitz-Kreuznach Panthers Black, or the very similar Stipula Ebony Black (which I use) and Montblanc Mystery Black.