10mg/ml of Propylene Glycol works. And what you're describing in the orginal post applies to Clonazolam.. for everyone, just shake it, and reheat it, it happens to everyone. I have not tried using Ethanol as the solvent of choice. VG should work. I would guess (don't quote me if I'm completely wrong on this) but I bet it would do the same thing in those solvents as well. And what Speedballs_over said, adding it Xmg/1ml at a time could help, but it probably won't help with the particles that much. Just shake/reheat it when you see it happening, and it should (has everytime I make my own solutions which are 10mg/ml in Propylene Glycol USP food grade) go back to being a clear solution.
And adding to what the above poster said, Clonazolam is a very seriously substance that shouldn't be taken lightly. Be careful with this substance. I use 10mg/ml as I have a fairly large Benzodiazepine tolerance, if you don't 1-5mg/ml will also work just fine. But please be really careful with this substance. It is/has slowly ruined my life.