I use pipnet on the rare occasions I ream my pipe, I know Geore Dibos prefers the triangular shaped reamer but that is a sure recipe for disaster if I used that one.
That was until I discovered popsicle sticks.
For initial cake removal (if it's heavy), I do this:
For everyday use, popsicle sticks are absolutely the ticket. Their edge shape and hardness is EXACTLY right for scraping without chipping. Push as hard as you want. Spin the bowl any way you want. The (slightly) flexible wood will conform to any chamber shape. Not just idiot-proof, but the result is perfect. Carbon made as smooth as an old-school chalk blackboard.