Other - crushed leaf to powder

[Valseedian]

I know the usual ideas, like blenders and coffee grinders, but does anyone have a good way to really powder crushed leaf kratom?

money is key, and makeshift is beautiful..


back story:
swim just received 115 grams of kratom through a reputable vendor and it's in crushed leaf. He's very used to making up 00 kratom caps, but always ordered powdered. He spent a few hours trying to break about 10 grams down to something cappable, but he only managed a very fine crushed leaf, and about a gram of powder when sifted.

so, any way to get it into a very fine powder?