hey....    in the experience of those who I have had the most contact with, using filter paper has had mixed results.  Apparently this procedure can work very well for some, but most testers I've talked to have had trouble with crystals melting into the paper, with naphtha not going through the paper fast, and with spills.  That's one of the big reasons why the rainbowserpent tek doesn't have filter papers.    If you can, either get another glass container or pour out of that one slowly.  It might take the second container, but eventually you should be able to pour out the naphtha while leaving the crystals stuck to one of the containers.