Let's think about this for a sec. You are going to put tobacco into the chamber, apply fire to the tobacco and smoke it for number of times in future. Give it a wildest guess as to what's going to happen to the inside of the chamber? If you guessed it will turn black, you guessed it right! Then, does it matter the coating comes off? That's not stain. That's coating to help with cake build up. Some people go ways to remove them before smoking. I don't. But rest assure, your Peterson chamber will turn black as a night soon enough if you smoke that pipe often enough.