I wasn't a regular user of this method- I only seen it done a few times while I smoked with others. They placed a chunk of hash on a safety pin, then took a lighter to the outside and burned the outside layer a bit. Some smoke did come off, but nothing you'll miss since you're rolling a joint anyway.
after they burned it- they crumbled it up. I suppose the burning process alters the state. After that.. shit I don't remember if they put tobacco/or pot in it or not. But it smoked great- if you don't mind the 'pop rocks' that come flying off.. be careful lol. Poprocks being popping chunks of hash that randomly shoot off the joint every once in awhile. Be careful
I wasn't a fan of this method, I'm sure there's a better way.