There's already a thread on this. The white stuff is kaolin, a harmless white clay.
http://boards.cannabis.com/cannabis-...bulb-vape.html
Mrs. Greenjeans Reviewed by Mrs. Greenjeans on . Homemade Vape! Hey all, after spending a good amount of time chipping away at the glass I finnaly made my own light bulb vaporizer. I must say the high is really great, But this is still all so wierd to me. Is it safe to smoke out of a lightbulb?, It gets really hot and it has its starting to get a few burn marks. What should I do? Is it cool? Or Should I toss it? Rating: 5