From what I've read (and learned from trying it when I was younger) doing this is a complete waste of perfectly good pills, shame on anyone who'd waste any type of benzo! From what I've read the heat destroys the active ingredient in Xanax (or any other benzo) before it it can become a vapor or smoke that you're able to inhale so you end up just inhaling all kinds of random chemicals that are really bad for you. Smoking any type of pills, even the ones that are still active when smoked (morphine and oxys for example), is still extremely bad for you because of the binders and other shit in the pills. So just eat the Xanax or if you want them to kick in faster put them under your tongue until they completely dissolve.
