I use a curved pointed chisel on my air hammer and made an adapter so I can get them all.

Have to be careful not to damage the pipe so you can see it on the outside. Also depending on the type of pi[pe you are gutting you have to be careful not to bugger up the screen that lines the pipe.

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!