Hi everybody!

This is a leafy vegetable of which my boyfriend are very fond. Depending on who you ask it's called gai lan, kai lan, Thai broccoli, mustard orchid, Chinese broccoli, or Chinese kale. In case you don't know, it has the stem shape, flowerish heads, and tenderness of broccolini but also nice long kale-ish leaves. The flavor is like halfway between kale and broccoli. Since we feel unsure what to correctly call it we just refer to it as broccokale. It's so delicious and very nutritious, too.
It has a Facebook page, of course, which you can visit
here.
Anyway, does anyone know the best way to clean this vegetable? It seems like no matter how much I soak and rinse and try to prep it I still end up with a little of this very fine grit in the final product. I guess maybe it's hiding in the little flower bud heads, but I don't want to ditch them or tear them apart. Any tips?