Leave it in the freezer (covered) for a few more hours, when you go to pour off the naphtha, the cyrstals will stick to the side. Don't be using filters, just pour slowly, and like I said, the good stuff will stay behind.
Dont worry about the loose crystals in the solution, when you go to pour off, they will adhere, as well. Just pour off slowly..
FYI- Anything I post here is just stuff made up by my crazy brother who lives in my closet. I feed him jellybeans.