Quote Originally Posted by LiquidOC
The black stuff you saw was the tar and gunk getting cleaned off of your pipe. It's rough and looks different now because it's clean, do you remember what it looked like when it was new? As in, before ANYONE smoked out of it? it probably looked just like this. Also, vinegar cannot kill you or anything, so it's more than likely 100% fine to keep on smoking out of that pipe.
I agree. I would guess that the vinegar broke the resin down, and formed a nice coating of the rest of the pipe. Clean the entire thing with salt and rubbing alcohol and you should be good to go..

There is nothing wrong with smoking out of stone compared to glass.. The damn pipe has been around longer than you.. LOL