Have a look for a high quality tinned furniture wax polish that has both carnauba wax and beeswax in it. That way you can use it to do as Chuck recommends, plus you can use it to put a nice shine on your bowl.
pstlpkr said drill the shank (he said sheepishly), but that is not such a bad idea if you have a 'Senior Pipe Reamer'. It's a great tool for anyone that buys estate pipes. One of the integrated tools that comes with the Senior, is a nice little hand drill bit. This will remove any build up of carbon on the inside of the shank and MAY solve the problem. A Senior can be picked up in the US for about $15 to $20 and they even have a 'Set' that has a few more tools in it, for $50ish. I got one a few months ago and it is a nice tool that does the job well. And as an estate pipe buyer, I wouldn't be without it.