Yeah, it's called resin. It's the resin that builds up from the smoke. It has a lot of tar and particulates, but gets you where you need to go. It works nicely in extreme conditions.

Some people think it's nasty. I think taking something that grows out of the ground, putting flame to it, and inhaling the smoke that forms is nasty, but I do it.

By the way, slipknotpsycho has a pretty good guide for getting all of the resin out of pipes, but I'm... not gonna look for it right now. I'm sure you could find it in two seconds though.