Now I've been told that only excellent quality tobacco leaves a fine white ash in your bowl post-smoking. I've had this happen to me on several occasions, and it has been a pain to clean up...the white ash sticks to the interior sides of my pipe's bowl. Is this a problem related to the pipe material? (I believe the pipe is a Dr. Grabow, but it was a factory second) Also, how should I clean it off? I've been (regretfully) reaming it off and that left scratches on the inside of my bowl. Help!