How do you prepare clonazepam for iv injection?

IMO your question is a little bit incomplete, I mean what kind of form of clonazepam you have? Becuz usually you dont need to "prepare" anything when injecting clonazepam vials. So I assume you have powdered clonazepam which means you probably crushed the pills

And I wont answer this question becuz injecting pills are dangerous to your cardiovascular system, specially your veins. Pills contain linkers, binders, fillers, colouring material etc so I dont want to be responsible if anything bad happens to you.

Also there ain't that much difference in clonazepam's bioavailability when compared to other routes of administrations. IMO intrabuccal, intrarectal or oral routes are the best option.

Besides IV clonazepam won't give you a rush (if you are planning to use it as recreationally which i have no doubt you will) like intravenously administered midazolam (a preanesthetic chemically similar to benzodiazepines - its a imidazolobenzodiazepine derivative)).

Health is no joke. We only live once so it doesn't worth risking your life for a thing like this.