I was actually going to submit this before I brute-force'd it and tore up the threads so I now have to throw the 3 dollar pen away altogether, but I wanted to try running warm water over it first, and then I got caught up in messing with it and.... well, now it's broken.
Anyway, I bought a Jinhao Shark 993 and wanted to fill it up along with a couple other piston pens I had on hand, and they all have gotten stuck, I assume because I closed them before testing them to write even a little. Lesson learned! But still, how do I open them???? This is the second one I've broken like this, actually, but at least this one didn't pull out the cartridge and get ink everywhere like the last one :'( Last time I get a Fountain Pen Revolution pen.