The Senior Pipe Reamer has been mentioned a lot here, but here's something to think about: the buildup inside the pipe happens so gradually that I often don't pay much attention to the diminishing volume of tobacco a pipe will hold. It's dark in there, hard to see. Being a total engineering geek, I calculated the difference in pipe volume for a pipe with a .75" diameter, one inch deep bowl. A mere tenth of an inch buildup (.05" all around) decreases chamber volume by 25%. Do the math! 

